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Parasitic Wasp Identification: How To Find Parasitic Wasp Larvae And Eggs

Parasitic Wasp Identification: How To Find Parasitic Wasp Larvae And Eggs


If you’re like most people, the idea of any type of wasp can set your nerves on edge. However, not all wasps are the scary, stinging type. In fact, we should all encourage the presence of parasitic wasps in gardens. Parasitic wasps, which aren’t the least bit interested in bothering humans, spend much of their lives working hard, either within or outside the body of a host insect.

Parasitic wasps parasitize different garden pests depending on species. These garden good guys can help control:

  • Aphids
  • Scale
  • Leafhoppers
  • Caterpillars
  • Roaches
  • Flies
  • Beetles
  • Whiteflies
  • Ticks

Read on to learn more about these beneficial insects.

Parasitic Wasp Identification

Parasitic wasps belong to the family Hymenoptera, which includes friendly honeybees and those angry, stinging wasps. Size of parasitic wasps vary greatly. Larger species can be nearly an inch (2.5 cm.) in length, while species that develop within the egg of a host insect tend to be miniscule.

When it comes to parasitic wasp identification, things get complicated. However, like other wasps, parasitic wasps have the appearance of a “waist,” which is actually the constriction between the insect’s abdomen and thorax. Most adults have two sets of wings, although some may be wingless in the adult stage.

Their antennae may vary as well and can be either short or long. Color? Again, there is no single answer, as parasitic wasps may be brown, black, or metallic green or blue. Some are marked with bright orange or yellow stripes.

Life Cycle of Parasitic Wasps

There are many types of parasitic wasps in gardens and some have extremely complex and interesting life cycles. For example, some species are able to reproduce without help of male wasps, which apparently don’t even exist; the female is able to do it all by herself without mating.

Some species produce several generations of offspring in a single season, while others take more than a year to develop a single adult.

So, the life cycle of parasitic wasps is something you may want to research on your own, as the topic is beyond the scope of this article. However, we can say that, in general, parasitic wasps advance through a complete life cycle–egg, larvae, pupae, and adult.

Parasitic Wasp Eggs

All female parasitic wasps possess an organ called an ovipositor, located at the tip of the abdomen. This long structure allows the wasps to deposit parasitic wasp eggs inside host insects, even when the hosts are hidden within tree bark or cocoons.

Most eggs contain a single larva, but some species produce multiple parasitic wasp larvae within a single egg.

Parasitic Wasp Larvae

Parasitic wasp larvae are garden heroes. Some species spend their entire development within the body of the host insect, while others may be embedded on the exterior of the host (which may be in various stages of development from egg to adult). Some parasitic wasps may start out on the exterior of the host, gradually working their way into the body.

The host pests may become inactive very quickly, or may continue to live normally for a short while with the parasitic wasp larva growing inside its body. Once the larva is nearly mature, however, the host is a goner for sure. The larva may exit the host before pupating or it may pupate inside the body of the deceased host.


Catalpa Worms and Parasitic Wasps

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One of the best natural insecticides is one you don’t have to purchase, mix or even apply. Tiny parasitic wasps use catalpa worms as a living incubator for their eggs and nursery for their hatchling larvae. The catalpa worms are pests of the catalpa tree (Catalpa species), feeding on the tree’s leaves, sometimes to the point of defoliation.


Wasp Life Cycle and Lifespan

Despite the diversity of wasps (there are over 100,000 species!), their life cycles are remarkably similar.

Wasps are typically divided into social and solitary wasps and this is a useful distinction for wasp life cycles as well. The approximately 1,000 species of social wasps, which follow the same general pattern of nesting behavior, development, and lifespan. The rest are solitary, and while some lay their eggs inside the body of another insect and others build nests, they are also united by a similar life cycle.

So, how do wasps reproduce? Like other insects, wasps lay eggs.

How long do wasps live?

The average lifespan of a wasp is typically about the length of a season or 3 to 6 weeks.

The life cycle of social wasps

The most common social wasps are paper wasps, yellow jackets, and hornets.

Their populations are characterized by colonies within papery nests either above or below ground composed of hexagonal cells for their larvae. These colonies typically only last the spring and summer and are not used again. However, in areas with mild winters, nests can be used for a year or more.

As spring begins, females that mated the previous fall emerge from the shelter in which they overwintered and go in search of a suitable nesting site. Once a site is found, these queen wasps begin to build a small nest. (For more information on nests, see our article on wasp nest identification!) In some paper wasp species, several females will start a colony together with one eventually emerging as the dominant queen and the others reduced to worker status.

Queens lay eggs in the cells of their nests, which hatch into larvae. The queen hunts insects, such as caterpillars, flies, grasshoppers, crickets, and even other wasps. She kills the insects, chews them up, and brings the slurry back to the nest to feed the larvae.

The larvae, or baby wasps, are white, legless, and grub-like. Once they reach their full larval size, they make a silk cap for their cell and mature into an adult wasp (pupate).

During this pupal stage, they become darker and segmented and grow their wings and legs. The process, from wasp egg to larva to pupa to adult, takes about a month, at which point adult workers emerge from the nest. The workers are sterile females and their job is to make the nest bigger and provision the rest of the eggs the queen lays.

Paper wasp nests tend not to be larger than an open hand and hold between 15 and 200 individuals, while yellow jacket nests grow much larger and can have between 1,500 and 15,000 individuals. Hornet nests lie in between, usually reaching populations of 300 to 1,000.

As the summer progresses, the workers feed themselves and the queen as well as the larvae, but to a lesser extent. Adult wasps eat nectar and other sugary substances. As the queen begins to lay fewer eggs and the average age of the colony is older, late in the summer, wasps begin to forage more heavily for themselves. This is the time when they become a nuisance to people on picnics or enjoying a sugary drink on the back porch.

Also near summer’s end, the queen lays the eggs which will become the next year’s queens and lays unfertilized eggs, which mature into males. Future queen cells are provisioned more than others. Fertile females and males leave the nest to find mates.

After mating, the males die, and the fertilized females find a sheltered place (under tree bark, in building crevices or burrowed underground) to hibernate through the winter. As cold weather sets in, the rest of the colony dies.

The life cycle of solitary wasps

Solitary wasps include mud daubers, cicada killers, and the non-stinging parasitic wasps. They differ from social wasps in that they do not form colonies. Instead, each female nests alone, providing food for her larvae before they hatch rather than progressively provisioning them after.

Mud daubers

Mud daubers emerge from pupal cases in the spring (except in the tropics, where they are continually active), then leave the nest to find a mate. Once fertilized (typically within 48 hours), females of most species gather mud and build their nest one cell at a time.

One species, however, the blue metallic mud dauber, uses the nests of other mud dauber species rather than building its own. Once a cell is complete, the female begins hunting for spiders, which she paralyzes with the venom of her sting and brings back to the nest. She lays an egg on one of the spiders and continues packing the cell full of spiders.

A single mud dauber cell can contain as many as 25 paralyzed spiders. Once the cell is full, she seals it up and begins a second cell. Black and yellow mud daubers typically build nests of up to 25 cells, while the organ pipe mud dauber builds up to 6 long pipes composed of multiple cells each.

The organ pipe mud dauber does something a little different. Unlike other wasps, the male stands guard over the nest, preventing intruders, including parasitic wasps and other males.

At the end of the season, usually, 3 to 6 weeks after emerging from the nest, the adult wasps die. Organ pipe mud daubers are a little different in this case, as well. Some overwinter as larvae, while others overwinter as adults and begin the reproductive cycle in the spring.

When the eggs hatch (usually after 1.5 to 3.5 days), the wasp larvae feed on the paralyzed spiders. They typically finish them off over the course of 1 to 3 weeks, depending on temperature. When the temperature drops, the larvae, now in their pre-pupal stage, go into diapause until the weather warms up again in the spring. Once the temperature rises, the larvae spin their cocoons and undergo the final stage of development before emerging to continue the cycle.

Cicada killers

Cicada killers have a similar life history to mud daubers, except that they dig burrows in which to lay their eggs and they specialize on cicadas, rather than spiders.

Each cicada killer burrow cell contains one egg and two or three cicadas. Eggs hatch in 2 to 3 days and the larvae feed for around 2 weeks before pupating. Like mud daubers, they emerge from the burrow in the spring to begin reproducing.

Parasitic wasps

Finally, parasitic wasps lay their eggs on or inside the bodies or eggs of host insects, such as caterpillars, aphids, sawflies, beetles, leafhoppers, thrips, and flies.

Once the eggs hatch, the larvae consume their host, pupate (either externally or within the remains of the host), and emerge to produce the next generation.

Conclusion

Although wasp species number in the hundreds of thousands, their life histories roughly fall into two categories depending on whether they are social or solitary. There is a bit more diversity within the solitary wasps. However, once you determine if you’re looking at a social or solitary wasp, you can figure out what role it plays in its population and in your garden.


A dark ending

A butterfly egg is tiny, but wasps can still develop inside it.В

When a wasp larva finds itself nestled inside a butterfly egg, it has all the sustenance it needs in that hard-shelled, protective host environment.В

One wasp, Hyposoter horticola, employs a sinister tactic to get inside its host, the egg of the Glanville Fritillary butterfly.

After keeping a close eye on a set of new butterfly eggs, a female wasp will lay its own inside them just before the tiny caterpillar is about to hatch.В

Wasp larvae spin their own tough cocoons after breaking free from inside the caterpillar's bodyВ В© Simon Shim/Shutterstock.com

Broad explains, 'The wasp larva sits tight inside the body of its host until the caterpillar is almost fully grown.В

'At that point, the wasp puts on a growth spurt. It eats the entire contents of the caterpillar's body and spins its own tough cocoon to pupate in, before emerging as another adult wasp.'


Predators, parasites and parasitoids

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Many animals are predators, parasites or parasitoids, using other animals as food. They use a great diversity of hunting strategies and behaviours to capture or feed on their prey. Invertebrate predators, parasites and parasitoids play an important role in keeping many animal populations under control.

Mud dauber wasps, Sphecidae, Hymenoptera, sting and paralyse spiders then seal them in mud nests for their young to feed.

This worm has lived inside this Huntsman Spider, eating its internal tissues.

Female Hadronyche sp from Clarence, Blue Mountains infested with parasitic mites. Close up of side of the head view

Red velvet mite, Order Acarina.

Planarian worm (right, yellow colour) attacking a coiled millipede (left). There are many non-insect invertebrates that are predators. The main group being the spiders, which are specialist predators. Spiders exploit an immense diversity of habitats and have developed some of the most sophisticated trapping and hunting techniques of any animal group. Other predatory invertebrates include scorpions, centipedes, predatory mites, predatory snails and slugs, nematodes and planarian worms.

What is a predator?

A predator is an organism that captures and eats another (the prey). This act is called predation.

In general, predators share the following features:

  • They are usually larger than their prey, or overwhelm their prey by attacking in large numbers like ants.
  • Most do not have specific prey and feed on a wide range of animals which, in some cases, they consume in large numbers. Lady beetles for example, can devour several hundred aphids in a day.
  • Some are specific, targeting a particular prey group. For example. feather-legged assassin bugs are known to feed only on ants.
  • Death to the victim is usually immediately after capture.
  • Adults or young may be predatory. In a number of cases the young are predatory but the adults are not. Adults of alderflies or dobsonflies do not eat but their aquatic larvae are fierce predators.

Which invertebrates are predators?

Predation in insects is common. The adults and young of groups such as mantids, dragonflies and damselflies, lacewings, scorpionflies and alderflies are entirely predacious. Even some moths, a group dominated by plant-feeding species, will bear offspring that are voracious predators.

There are also many non-insect invertebrates that are predators. The main group being the spiders, which are specialist predators. Spiders exploit an immense diversity of habitats and have developed some of the most sophisticated trapping and hunting techniques of any animal group. Other predatory invertebrates include scorpions, centipedes, predatory mites, predatory snails and slugs, nematodes and planarian worms.

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What do invertebrate predators feed on?

Invertebrate predators usually feed on other invertebrates, however some feed on fish, frogs, small mammals and birds, in the case of certain large spiders and centipedes. Generally, predators kill to feed themselves but in some cases they hunt for their offspring. Wasps and ants primarily feed on plant liquids as adults but their offspring require solid foods. The adults capture prey and deliver it to their young.

Invertebrate predators usually eat their prey while it is still alive. They do this either with biting and chewing mouthparts or by piercing the body and sucking out the victim's internal fluids. The latter may also involve injecting a cocktail of salivary secretions that act to paralyse the prey and liquefy its tissue.

How do invertebrates capture their prey?

The methods by which invertebrate predators catch prey are incredibly diverse and in some cases very complex.

Invertebrate predators are either passive or active:

  • Passive predators tend to sit and wait for prey to come close. Mantids wait poised for long periods of time for prey to come within the grasp of their powerful forelegs.
  • Active predators are those that search or hunt for their prey. Dragonflies and Robber flies use speed and agility to pluck prey from the air, while some spiders construct casting nets that are thrown over prey as they fly past.

Some active predators specialise in capturing and eating other predators. The Fringed Jumping Spider specialises in eating other spiders. It will vibrate the web of the intended prey in an attempt to imitate a victim caught in it. The web-building spider comes to investigate what they believe is food, to find they themselves are on the menu.

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Considerations

Braconid wasps are harmless to people because they do not sting. The short six-week life cycle of the catalpa sphinx moth makes it possible for three or four generations to occur in a single year, which means that eggs, larvae, pupae and adult moths from different generations may be present all at once on the same tree. The catalpa tree’s prolific seed production, coupled with its high germination rate, places it on some invasive plant species lists. In other areas where it is not yet an invasive threat, it may be on the watch list for its invasive potential.

Victoria Lee Blackstone is a horticulturist and a professional writer who has authored research-based scientific/technical papers, horticultural articles, and magazine and newspaper articles. After studying botany and microbiology at Clemson University, Blackstone was hired as a University of Georgia Master Gardener Coordinator. She is also a former mortgage acquisition specialist for Freddie Mac in Atlanta, GA.


Contents

  • 1 Taxonomy and phylogeny
    • 1.1 Paraphyletic grouping
    • 1.2 Fossils
    • 1.3 Diversity
  • 2 Sociality
    • 2.1 Social wasps
    • 2.2 Solitary wasps
  • 3 Biology
    • 3.1 Anatomy
    • 3.2 Diet
    • 3.3 Sex determination
    • 3.4 Inbreeding avoidance
  • 4 Ecology
    • 4.1 As pollinators
    • 4.2 As parasitoids
    • 4.3 As parasites
    • 4.4 As predators
    • 4.5 As models for mimics
    • 4.6 As prey
  • 5 Relationship with humans
    • 5.1 As pests
    • 5.2 In horticulture
    • 5.3 In sport
    • 5.4 In fashion
    • 5.5 In literature
    • 5.6 In military names
  • 6 See also
  • 7 Notes
  • 8 References
  • 9 Sources
  • 10 External links

Paraphyletic grouping

The wasps are a cosmopolitan paraphyletic grouping of hundreds of thousands of species, [1] [2] consisting of the narrow-waisted clade Apocrita without the ants and bees. [3] The Hymenoptera also contain the somewhat wasplike but unwaisted Symphyta, the sawflies.

The term wasp is sometimes used more narrowly for members of the Vespidae, which includes several eusocial wasp lineages, such as yellowjackets (the genera Vespula and Dolichovespula), hornets (genus Vespa), and members of the subfamily Polistinae.

Fossils

Hymenoptera in the form of Symphyta (Xyelidae) first appeared in the fossil record in the Lower Triassic. Apocrita, wasps in the broad sense, appeared in the Jurassic, and had diversified into many of the extant superfamilies by the Cretaceous they appear to have evolved from the Symphyta. [4] Fig wasps with modern anatomical features first appeared in the Lower Cretaceous of the Crato Formation in Brazil, some 65 million years before the first fig trees. [5]

The Vespidae include the extinct genus Palaeovespa, seven species of which are known from the Eocene rocks of the Florissant fossil beds of Colorado and from fossilised Baltic amber in Europe. [6] Also found in Baltic amber are crown wasps of the genus Electrostephanus. [7] [8]

Diversity

Wasps are a diverse group, estimated at well over a hundred thousand described species around the world, and a great many more as yet undescribed. [9] [a] For example, almost every one of some 1000 species of tropical fig trees has its own specific fig wasp (Chalcidoidea) that has co-evolved with it and pollinates it. [10]

Many wasp species are parasitoids the females deposit eggs on or in a host arthropod on which the larvae then feed. Some larvae start off as parasitoids, but convert at a later stage to consuming the plant tissues that their host is feeding on. In other species, the eggs are laid directly into plant tissues and form galls, which protect the developing larvae from predators but not necessarily from other parasitic wasps. In some species, the larvae are predatory themselves the wasp eggs are deposited in clusters of eggs laid by other insects, and these are then consumed by the developing wasp larvae. [10]

The largest social wasp is the Asian giant hornet, at up to 5 centimetres (2.0 in) in length. [11] The various tarantula hawk wasps are of a similar size [12] and can overpower a spider many times its own weight, and move it to its burrow, with a sting that is excruciatingly painful to humans. [13] The solitary giant scoliid, Megascolia procer, with a wingspan of 11.5 cm, [14] has subspecies in Sumatra and Java [15] it is a parasitoid of the Atlas beetle Chalcosoma atlas. [16] The female giant ichneumon wasp Megarhyssa macrurus is 12.5 centimetres (5 in) long including its very long but slender ovipositor which is used for boring into wood and inserting eggs. [17] The smallest wasps are solitary chalcid wasps in the family Mymaridae, including the world's smallest known insect, Dicopomorpha echmepterygis (139 micrometres long) and Kikiki huna with a body length of only 158 micrometres, the smallest known flying insect. [18]

There are estimated to be 100,000 species of ichneumonoid wasps in the families Braconidae and Ichneumonidae. These are almost exclusively parasitoids, mostly utilising other insects as hosts. Another family, the Pompilidae, is a specialist parasitoid of spiders. [10] Some wasps are even parasitoids of parasitoids the eggs of Euceros are laid beside lepidopteran larvae and the wasp larvae feed temporarily on their haemolymph, but if a parasitoid emerges from the host, the hyperparasites continue their life cycle inside the parasitoid. [19] Parasitoids maintain their extreme diversity through narrow specialism. In Peru, 18 wasp species were found living on 14 fly species in only two species of Gurania climbing squash. [20] [21]

Megascolia procer, a giant solitary species from Java in the Scoliidae. This specimen's length is 77mm and its wingspan is 115mm. [b] [14]

Megarhyssa macrurus, a parasitoid. The body of a female is 50mm long, with a c. 100mm ovipositor

Tarantula hawk wasp dragging an orange-kneed tarantula to her burrow it has the most painful sting of any wasp. [13]

Social wasps

Of the dozens of extant wasp families, only the family Vespidae contains social species, primarily in the subfamilies Vespinae and Polistinae. With their powerful stings and conspicuous warning coloration, often in black and yellow, social wasps are frequent models for Batesian mimicry by non-stinging insects, and are themselves involved in mutually beneficial Müllerian mimicry of other distasteful insects including bees and other wasps. All species of social wasps construct their nests using some form of plant fiber (mostly wood pulp) as the primary material, though this can be supplemented with mud, plant secretions (e.g., resin), and secretions from the wasps themselves multiple fibrous brood cells are constructed, arranged in a honeycombed pattern, and often surrounded by a larger protective envelope. Wood fibres are gathered from weathered wood, softened by chewing and mixing with saliva. The placement of nests varies from group to group yellow jackets such as Dolichovespula media and D. sylvestris prefer to nest in trees and shrubs Protopolybia exigua attaches its nests on the underside of leaves and branches Polistes erythrocephalus chooses sites close to a water source. [22]

Other wasps, like Agelaia multipicta and Vespula germanica, like to nest in cavities that include holes in the ground, spaces under homes, wall cavities or in lofts. While most species of wasps have nests with multiple combs, some species, such as Apoica flavissima, only have one comb. [23] The length of the reproductive cycle depends on latitude Polistes erythrocephalus, for example, has a much longer (up to 3 months longer) cycle in temperate regions. [24]

Solitary wasps

The vast majority of wasp species are solitary insects. [10] [25] Having mated, the adult female forages alone and if it builds a nest, does so for the benefit of its own offspring. Some solitary wasps nest in small groups alongside others of their species, but each is involved in caring for its own offspring (except for such actions as stealing other wasps’ prey or laying in other wasp's nests). There are some species of solitary wasp that build communal nests, each insect having its own cell and providing food for its own offspring, but these wasps do not adopt the division of labour and the complex behavioural patterns adopted by eusocial species. [25]

Adult solitary wasps spend most of their time in preparing their nests and foraging for food for their young, mostly insects or spiders. Their nesting habits are more diverse than those of social wasps. Many species dig burrows in the ground. [25] Mud daubers and pollen wasps construct mud cells in sheltered places. [26] Potter wasps similarly build vase-like nests from mud, often with multiple cells, attached to the twigs of trees or against walls. [27]

Predatory wasp species normally subdue their prey by stinging it, and then either lay their eggs on it, leaving it in place, or carry it back to their nest where an egg may be laid on the prey item and the nest sealed, or several smaller prey items may be deposited to feed a single developing larva. Apart from providing food for their offspring, no further maternal care is given. Members of the family Chrysididae, the cuckoo wasps, are kleptoparasites and lay their eggs in the nests of unrelated host species. [25]

Anatomy

Like all insects, wasps have a hard exoskeleton which protects their three main body parts, the head, the mesosoma (including the thorax and the first segment of the abdomen) and the metasoma. There is a narrow waist, the petiole, joining the first and second segments of the abdomen. The two pairs of membranous wings are held together by small hooks and the forewings are larger than the hind ones in some species, the females have no wings. In females there is usually a rigid ovipositor which may be modified for injecting venom, piercing or sawing. [28] It either extends freely or can be retracted, and may be developed into a stinger for both defence and for paralysing prey. [29]

In addition to their large compound eyes, wasps have several simple eyes known as ocelli, which are typically arranged in a triangle just forward of the vertex of the head. Wasps possess mandibles adapted for biting and cutting, like those of many other insects, such as grasshoppers, but their other mouthparts are formed into a suctorial proboscis, which enables them to drink nectar. [30]

The larvae of wasps resemble maggots, and are adapted for life in a protected environment this may be the body of a host organism or a cell in a nest, where the larva either eats the provisions left for it or, in social species, is fed by the adults. Such larvae have soft bodies with no limbs, and have a blind gut (presumably so that they do not foul their cell). [31]

Adult solitary wasps mainly feed on nectar, but the majority of their time is taken up by foraging for food for their carnivorous young, mostly insects or spiders. Apart from providing food for their larval offspring, no maternal care is given. [25] Some wasp species provide food for the young repeatedly during their development (progressive provisioning). [32] Others, such as potter wasps (Eumeninae) [33] and sand wasps (Ammophila, Sphecidae), [34] repeatedly build nests which they stock with a supply of immobilised prey such as one large caterpillar, laying a single egg in or on its body, and then sealing up the entrance (mass provisioning). [35]

Predatory and parasitoidal wasps subdue their prey by stinging it. They hunt a wide variety of prey, mainly other insects (including other Hymenoptera), both larvae and adults. [25] The Pompilidae specialize in catching spiders to provision their nests. [36]

Some social wasps are omnivorous, feeding on fallen fruit, nectar, and carrion such as dead insects. Adult male wasps sometimes visit flowers to obtain nectar. Some wasps, such as Polistes fuscatus, commonly return to locations where they previously found prey to forage. [37] In many social species, the larvae exude copious amounts of salivary secretions that are avidly consumed by the adults. These include both sugars and amino acids, and may provide essential protein-building nutrients that are otherwise unavailable to the adults (who cannot digest proteins). [38]

Sex determination

In wasps, as in other Hymenoptera, sex is determined by a haplodiploid system, which means that females are unusually closely related to their sisters, enabling kin selection to favour the evolution of eusocial behaviour. Females are diploid, meaning that they have 2n chromosomes and develop from fertilized eggs. Males, called drones, have a haploid (n) number of chromosomes and develop from an unfertilized egg. [29] Wasps store sperm inside their body and control its release for each individual egg as it is laid if a female wishes to produce a male egg, she simply lays the egg without fertilizing it. Therefore, under most conditions in most species, wasps have complete voluntary control over the sex of their offspring. [25] Experimental infection of Muscidifurax uniraptor with the bacterium Wolbachia induced thelytokous reproduction and an inability to produce fertile, viable male offspring. [39]

Inbreeding avoidance

Females of the solitary wasp parasitoid Venturia canescens can avoid mating with their brothers through kin recognition. [40] In experimental comparisons, the probability that a female will mate with an unrelated male was about twice as high as the chance of her mating with brothers. Female wasps appear to recognize siblings on the basis of a chemical signature carried or emitted by males. [40] Sibling-mating avoidance reduces inbreeding depression that is largely due to the expression of homozygous deleterious recessive mutations. [41]

As pollinators

While the vast majority of wasps play no role in pollination, a few species can effectively transport pollen and pollinate several plant species. [42] Since wasps generally do not have a fur-like covering of soft hairs and a special body part for pollen storage (pollen basket) as some bees do, pollen does not stick to them well. [43] However it has been shown that even without hairs, several wasp species are able to effectively transport pollen, therefore contributing for potential pollination of several plant species. [44]

Pollen wasps in the subfamily Masarinae gather nectar and pollen in a crop inside their bodies, rather than on body hairs like bees, and pollinate flowers of Penstemon and the water leaf family, Hydrophyllaceae. [45]

The Agaonidae (fig wasps) are the only pollinators of nearly 1000 species of figs, [43] and thus are crucial to the survival of their host plants. Since the wasps are equally dependent on their fig trees for survival, the coevolved relationship is fully mutualistic. [46]

As parasitoids

Most solitary wasps are parasitoids. [47] As adults, those that do feed typically only take nectar from flowers. Parasitoid wasps are extremely diverse in habits, many laying their eggs in inert stages of their host (egg or pupa), sometimes paralysing their prey by injecting it with venom through their ovipositor. They then insert one or more eggs into the host or deposit them upon the outside of the host. The host remains alive until the parasitoid larvae pupate or emerge as adults. [48]

The Ichneumonidae are specialized parasitoids, often of Lepidoptera larvae deeply buried in plant tissues, which may be woody. For this purpose, they have exceptionally long ovipositors they detect their hosts by smell and vibration. Some of the largest species, including Rhyssa persuasoria and Megarhyssa macrurus, parasitise horntails, large sawflies whose adult females also have impressively long ovipositors. [49] Some parasitic species have a mutualistic relationship with a polydnavirus that weakens the host's immune system and replicates in the oviduct of the female wasp. [10]

One family of chalcid wasps, the Eucharitidae, has specialized as parasitoids of ants, most species hosted by one genus of ant. Eucharitids are among the few parasitoids that have been able to overcome ants' effective defences against parasitoids. [50] [51] [52]

As parasites

Many species of wasp, including especially the cuckoo or jewel wasps (Chrysididae), are kleptoparasites, laying their eggs in the nests of other wasp species to exploit their parental care. Most such species attack hosts that provide provisions for their immature stages (such as paralyzed prey items), and they either consume the provisions intended for the host larva, or wait for the host to develop and then consume it before it reaches adulthood. An example of a true brood parasite is the paper wasp Polistes sulcifer, which lays its eggs in the nests of other paper wasps (specifically Polistes dominula), and whose larvae are then fed directly by the host. [53] [54] Sand wasps Ammophila often save time and energy by parasitising the nests of other females of their own species, either kleptoparasitically stealing prey, or as brood parasites, removing the other female's egg from the prey and laying their own in its place. [55] According to Emery's rule, social parasites, especially among insects, tend to parasitise species or genera to which they are closely related. [56] [57] For example, the social wasp Dolichovespula adulterina parasitises other members of its genus such as D. norwegica and D. arenaria. [58] [59]

As predators

Many wasp lineages, including those in the families Vespidae, Crabronidae, Sphecidae, and Pompilidae, attack and sting prey items that they use as food for their larvae while Vespidae usually macerate their prey and feed the resulting bits directly to their brood, most predatory wasps paralyze their prey and lay eggs directly upon the bodies, and the wasp larvae consume them. Apart from collecting prey items to provision their young, many wasps are also opportunistic feeders, and will suck the body fluids of their prey. Although vespid mandibles are adapted for chewing and they appear to be feeding on the organism, they are often merely macerating it into submission. The impact of the predation of wasps on economic pests is difficult to establish. [60]

The roughly 140 species of beewolf (Philanthinae) hunt bees, including honeybees, to provision their nests the adults feed on nectar and pollen. [61]

As models for mimics

With their powerful stings and conspicuous warning coloration, social wasps are the models for many species of mimic. Two common cases are Batesian mimicry, where the mimic is harmless and is essentially bluffing, and Müllerian mimicry, where the mimic is also distasteful, and the mimicry can be considered mutual. Batesian mimics of wasps include many species of hoverfly and the wasp beetle. Many species of wasp are involved in Müllerian mimicry, as are many species of bee. [62]

As prey

While wasp stings deter many potential predators, bee-eaters (in the bird family Meropidae) specialise in eating stinging insects, making aerial sallies from a perch to catch them, and removing the venom from the stinger by repeatedly brushing the prey firmly against a hard object, such as a twig. [63] The honey buzzard attacks the nests of social hymenopterans, eating wasp larvae it is the only known predator of the dangerous [64] Asian giant hornet or "yak-killer" (Vespa mandarinia). [65] Likewise, roadrunners are the only real predators of tarantula hawk wasps. [66]

Minute pollinating fig wasps, Pleistodontes: the trees and wasps have coevolved and are mutualistic.

Latina rugosa planidia (arrows, magnified) attached to an ant larva the Eucharitidae are among the few parasitoids able to overcome the strong defences of ants.

The Chrysididae, such as this Hedychrum rutilans, are known as cuckoo or jewel wasps for their parasitic behaviour and metallic iridescence.

European beewolf Philanthus triangulum provisioning her nest with a honeybee

Wasp beetle Clytus arietis is a Batesian mimic of wasps.

Bee-eaters such as Merops apiaster specialise in feeding on bees and wasps.

As pests

Social wasps are considered pests when they become excessively common, or nest close to buildings. People are most often stung in late summer, when wasp colonies stop breeding new workers the existing workers search for sugary foods and are more likely to come into contact with humans if people then respond aggressively, the wasps sting. [67] Wasp nests made in or near houses, such as in roof spaces, can present a danger as the wasps may sting if people come close to them. [68] Stings are usually painful rather than dangerous, but in rare cases, people may suffer life-threatening anaphylactic shock. [69]

In horticulture

Some species of parasitic wasp, especially in the Trichogrammatidae, are exploited commercially to provide biological control of insect pests. [2] [70] One of the first species to be used was Encarsia formosa, a parasitoid of a range of species of whitefly. It entered commercial use in the 1920s in Europe, was overtaken by chemical pesticides in the 1940s, and again received interest from the 1970s. Encarsia is used especially in greenhouses to control whitefly pests of tomato and cucumber, and to a lesser extent of aubergine (eggplant), flowers such as marigold, and strawberry. [71] Several species of parasitic wasp are natural predators of aphids and can help to control them. [72] For instance, Aphidius matricariae is used to control the peach-potato aphid. [73]

Encarsia formosa, a parasitoid, is sold commercially for biological control of whitefly, an insect pest of tomato and other horticultural crops.

Tomato leaf covered with nymphs of whitefly parasitised by Encarsia formosa

In sport

Wasps RFC is an English professional rugby union team originally based in London but now playing in Coventry the name dates from 1867 at a time when names of insects were fashionable for clubs. The club's first kit is black with yellow stripes. [74] The club has an amateur side called Wasps FC. [75]

Among the other clubs bearing the name are a basketball club in Wantirna, Australia, [76] and Alloa Athletic F.C., a football club in Scotland. [77]

In fashion

Wasps have been modelled in jewellery since at least the nineteenth century, when diamond and emerald wasp brooches were made in gold and silver settings. [78] A fashion for wasp waisted female silhouettes with sharply cinched waistlines emphasizing the wearer's hips and bust arose repeatedly in the nineteenth and twentieth centuries. [79] [80]

In literature

The Ancient Greek playwright Aristophanes wrote the comedy play Σφῆκες (Sphēkes), The Wasps, first put on in 422 BC. The "wasps" are the chorus of old jurors. [81]

It flew, he is convinced, within a yard of him, struck the ground, rose again, came down again perhaps thirty yards away, and rolled over with its body wriggling and its sting stabbing out and back in its last agony. He emptied both barrels into it before he ventured to go near. When he came to measure the thing, he found it was twenty-seven and a half inches across its open wings, and its sting was three inches long. . The day after, a cyclist riding, feet up, down the hill between Sevenoaks and Tonbridge, very narrowly missed running over a second of these giants that was crawling across the roadway. [82]

Wasp (1957) is a science fiction book by the English writer Eric Frank Russell it is generally considered Russell's best novel. [84] In Stieg Larsson's book The Girl Who Played with Fire (2006) and its film adaptation, Lisbeth Salander has adopted her kickboxing ringname, "The Wasp", as her hacker handle and has a wasp tattoo on her neck, indicating her high status among hackers, unlike her real world situation, and that like a small but painfully stinging wasp, she could be dangerous. [85]

Parasitoidal wasps played an indirect role in the nineteenth-century evolution debate. The Ichneumonidae contributed to Charles Darwin's doubts about the nature and existence of a well-meaning and all-powerful Creator. In an 1860 letter to the American naturalist Asa Gray, Darwin wrote:

I own that I cannot see as plainly as others do, and as I should wish to do, evidence of design and beneficence on all sides of us. There seems to me too much misery in the world. I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of caterpillars, or that a cat should play with mice. [86]

In military names

With its powerful sting and familiar appearance, the wasp has given its name to many ships, aircraft and military vehicles. [87] Nine ships and one shore establishment of the Royal Navy have been named HMS Wasp, the first an 8-gun sloop launched in 1749. [88] Eleven ships of the United States Navy have similarly borne the name USS Wasp, the first a merchant schooner acquired by the Continental Navy in 1775. [89] The eighth of these, an aircraft carrier, gained two Second World War battle stars, prompting Winston Churchill to remark "Who said a Wasp couldn't sting twice?" [87] In the Second World War, a German self-propelled howitzer was named Wespe, [90] while the British developed the Wasp flamethrower from the Bren Gun Carrier. [91] In aerospace, the Westland Wasp was a military helicopter developed in England in 1958 and used by the Royal Navy and other navies. [92] The AeroVironment Wasp III is a miniature UAV developed for United States Air Force special operations. [93]


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