GeneticsIn wasps, as in other Hymenoptera, sexes are significantly genetically different. Females have 2n number of chromosomes and come about from fertilized eggs. Males, in contrast, have a haploid (n) number of chromosomes and develop from an unfertilized egg. 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. Anatomy and sex Anatomically, there is a great deal of variation between different types of wasp. Like all insects, wasps have a hard exoskeleton covering their three main body parts. These parts are known as the head, mesosoma and metasoma. Wasps also have a constricted region joining the first and second segments of the abdomen (the first segment is part of the mesosoma, the second is part of the metasoma) known as the petiole. Like all insects, wasps have three sets of two legs. In addition to their compound eyes, wasps also have several simple eyes known as ocelli. These are typically arranged in a triangular formation just forward of an area of the head known as the vertex.It is possible to distinguish between sexes of some wasp species based on the number of divisions on their antennae. For example, male yellowjacket wasps have 13 divisions per antenna, while females have 12. Males can in some cases be differentiated from females by virtue of having an additional visible segment in the metasoma. The difference between sterile female worker wasps and queens also varies between species but generally the queen is noticeably larger than both males and other females.Wasps can be differentiated from bees, which have a flattened hind basitarsus. Unlike bees, wasps generally lack plumose hairs. Diet
Generally, wasps are parasites or parasitoids as larvae, and feed on nectar only as adults. Many wasps are predatory, using other insects (often paralyzed) as food for their larvae. In parasitic species, the first meals are almost always derived from the host in which the larvae grow.Several types of social wasps are omnivorous, feeding on a variety of fallen fruit, nectar, and carrion. Some of these social wasps, such as yellow jackets, may scavenge for dead insects to provide for their young. In many social species, the larvae provide sweet secretions that are consumed by adults. Adult male wasps sometimes visit flowers to obtain nectar to feed on in much the same manner as honey bees. Furthermore some wasps, such as the Polistes fuscatus, may commonly return to locations to forage in which they have previously found prey. Role in ecosystem
PollinationWhile the vast majority of wasps play no role in pollination, a few species can effectively transport pollen and therefore contribute for the pollination of several plant species, being potential or even efficient pollinators; in a few cases such as figs pollinated by fig wasps, they are the only pollinators, and thus they are crucial to the survival of their host plants. Wasp parasitismWith most species, adult parasitic wasps themselves do not take any nutrients from their prey, and, much like bees, butterflies, and moths, those that do feed as adults typically derive all of their nutrition from nectar. Parasitic wasps are typically parasitoids, and extremely diverse in habits, many laying their eggs in inert stages of their host (egg or pupa), or sometimes paralyzing 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 host externally. The host remains alive until the parasitoid larvae are mature, usually dying either when the parasitoids pupate, or when they emerge as adults.Wasps can also act as 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.