Parasitoid wasp - Wikipedia
As early as , scientists realised that the wasps were also injecting the caterpillars with some kind of small particle, alongside their eggs. These wasps lay their eggs inside other insects, which their larvae then eat from within. The wasp may stab the caterpillar in this way a dozen times When the parasitoid larva loses connection with its egg, it fuses its. They are parasitoids which lay their eggs in or on the caterpillars of other insect of insect viruses that have a mutualistic relationship with parasitic wasps.
One family, the Eucharitidsuse ant larvae as hosts. They lay their eggs on plants near ant nests.
What Is the Relationship Between Wasps & Caterpillars? | Animals - porkostournaments.info
When the wasp larvae emerge, they sit around until they encounter an ant heading back to its nest. Other parasitoids must venture into truly dangerous territory Once inside the ant nest, the parasitoid larva attaches to an ant larva. It emits a chemical bouquet so similar to its ant hosts that the ants accept its presence. Even when it becomes an adult wasp, the ants treat it as one of their own, grooming and feeding it.
Parasitic wasp - Simple English Wikipedia, the free encyclopedia
Before the ant-mimicking odour wears off, the wasp emerges from the nest and leaves. Other parasitoids must venture into truly dangerous territory to find their hosts. One Japanese species has learned to scuba-dive. Agriotypus gracilis lays her eggs in the pupae of a caddisfly called Goera japonica.
Like all caddisflies, these larvae build protective cases out of silk and sand grains. They also live inches underwater. Larvae that develop inside a host's body need to obtain some air To reach one, the female wasp crawls down a plant stem or the side of an exposed stone. She can survive about 14 minutes underwater.
Her thick hair forms a sort of bubble that allows her to breathe. After laying an egg, the female floats to the surface to look for another pupa. Once the larvae hatch, they usually eat up their host. Larvae like these have it easy.The Ichneumon Wasp
They are outside the host's body, so can breathe normally. However, larvae that develop inside a host's body need to obtain some air. Encyrtus infidus is a parasitoid on the scale insect Lecanium kunoensis sometimes called Eulecanium kunoense.
Many parasitoid larvae develop on one scale larvaand use it as a buffet. They turn their hosts into their personal bodyguards At first, the larvae remain attached to the egg from which they hatched by a stalk. This helps them get their air. Later, the scale's innards get crowded, the larvae start competing for space, and the stalk gets cut.
But the wasp larva has a solution. The scale larva has a network of tubes that supply air throughout its body, called trachea. Each trachea ends in an opening called a spiracle, through which the scale larva exchanges air with its surroundings. When the parasitoid larva loses connection with its egg, it fuses its spiracles with the tracheal system of the scale and "steals" air until it pupates. Other parasitoids do more than steal their hosts' air.
They turn their hosts into their personal bodyguards. Among the leafy undergrowth of Brazil, the parasitoid Glyptapanteles seeks out caterpillars of the moth Thyrinteina leucoceraea and deposits up to 80 eggs. The host caterpillar continues feeding even after the larvae hatch from the eggs.
It swings its head violently from side to side to keep predators at bay The parasitoids feed on the caterpillar's insides until they are ready to pupate. Then, almost all of them eat their way out of the still-living caterpillar, and spin a cocoon on a nearby twig or leaf.
However, a few of them stay inside the caterpillar. Their job is to control the caterpillar and make it guard their pupating brothers and sisters. The beleaguered caterpillar stops eating. It uses its body, which by this point is riddled with holes, as a tent to protect the pupae.
It also swings its head violently from side to side to keep predators at bay.
Parasitic Wasp Larvae Emerging from Caterpillar
Once the wasps emerge, the caterpillar dies. After pupation, the adult has to emerge from its host's body. This is the particularly gruesome bit, and resembles nothing so much as the famous chest-burster scene from Alien. The wasp comes forth very largely covered with body fluids and fragments of tissue of the host Writing inCurtis Clausen explained that the adult wasp " must first effect a break in the puparium which surrounds it and then scrape or bite away a varying amount of host viscera or tissue, and finally cut a hole in the heavily chitinised integument… " All this biting and cutting creates an almighty mess, and "the wasp comes forth very largely covered with body fluids and fragments of tissue of the host.
Once this is over with, the adult wasps have one task left in order to complete the cycle. View image of An ichneumonid wasp prepares to lay its eggs Credit: In some parasitoids, males fly around searching for chemical signals secreted by receptive females.
But sometimes the roles are reversed. In some species of the genus Melittobiawhich infects the larvae of solitary bees and wasps, males produce odours that attract females in droves.
Melittobia lays eggs in its hosts just before they pupate. The female stings the host into submission, then lays a cluster of eggs on the outer surface.
This simple act launches a bizarre sexual drama. The larvae feed through the host's skin, pupate and become wasps. Almost all of them are female. If the host is large enough, the eggs develop rapidly into short-winged females. These lay even more eggs, draining the host completely. Brothers fight one another for access to their emerging sisters Eggs laid later develop into long-winged females, which chew through the host cocoon and fly out to find more victims.
Meanwhile, within the cocoon the few blind males begin courting the females. They raise and lower their legs, stroke the females with their legs and antennae, and flutter their wings, according to a study by Robert Matthews of the University of Georgia in Athens.
Competition among the males is fierce. Sometimes, all the males wind up dead. The females are then left without mates. So they make some more. A female wasp finds a new host and lays a few eggs, usually less than ten. All these eggs develop into males. She stays around, stroking her sons with her antennae, watching them grow into pupae and then emerge as adults. While most female parasitoids abandon their offspring as soon as the legs are laid, Melittobia females can be positively maternal.
When the first adult male emerges, the female mates with him. Having been fertilised by her own son, she lays a full clutch of eggs on the same host. View image of Copidosoma floridanum eggs hatching Credit: The host egg hatches and the host larva grows, evidently unaware of the parasitoid larvae inside it. Most ectoparasitoid wasps are idiobiont, as the host could damage or dislodge the external parasitoid if allowed to move or moult. Most endoparasitoid wasps are koinobionts, giving them the advantage of a host that continues to grow larger and remains able to avoid predators.
Hosts[ edit ] Many parasitoid wasps use larval Lepidoptera as hosts, but some groups parasitize different host life stages egg, larva or nymph, pupa, adult of nearly all other orders of insects, especially ColeopteraDipteraHemiptera and other Hymenoptera.
Some attack arthropods other than insects: Adult female wasps of most species oviposit into their hosts' bodies or eggs. Some also inject a mix of secretory products that paralyse the host or protect the egg from the host's immune system; these include polydnavirusesovarian proteins, and venom. If a polydnavirus is included, it infects the nuclei of host hemocytes and other cells, causing symptoms that benefit the parasite.
Host size is important for the development of the parasitoid, as the host is its entire food supply until it emerges as an adult; small hosts often produce smaller parasitoids.
This may both deter rivals from ovipositing, and signal to itself that no further egg is needed in that host, effectively reducing the chances that offspring will have to compete for food and increasing the offspring's survival.
On or inside the host the parasitoid egg hatches into a larva or two or more larvae polyembryony. Endoparasitoid eggs can absorb fluids from the host body and grow several times in size from when they were first laid before hatching.
The first instar larvae is often highly mobile and may have strong mandibles or other structures to compete with other parasitiod larvae. The following instars are generally more grub-like.
Parasitoid larvae have incomplete digestive systems with no rear opening. This prevents the hosts from being contaminated by their wastes. The larva feeds on the host's tissues until ready to pupate; by then the host is generally either dead or almost so.
A meconiumor the accumulated wastes from the larva is cast out as the larva transitions to a prepupa. In either case it then generally spins a cocoon and pupates. As adults, parasitoid wasps feed primarily on nectar from flowers. Females of some species will also drink hemolymph from hosts to gain additional nutrients for egg production.
Mutualism with polydnavirus[ edit ] Main article: Polydnavirus Polydnaviruses are a unique group of insect viruses that have a mutualistic relationship with some parasitic wasps. The polydnavirus replicates in the oviducts of an adult female parasitoid wasp. The wasp benefits from this relationship because the virus provides protection for the parasitic larvae inside the host, i by weakening the host's immune system and ii by altering the host's cells to be more beneficial to the parasite.
The relationship between these viruses and the wasp is obligatory in the sense that all individuals are infected with the viruses; the virus has been incorporated in the wasp's genome and is inherited.