Like all other insects, wasps are
invertebrate arthropods that reproduce using a larval stage. They have two
pairs of wings used for flight. Females have a stinger, which evolved from a
female sex organ called an ovipositor, thus being absent in males. Both wasp adults and larvae are the leading
parasites in the insect world, and there is a wasp parasite for practically
every pest insect. The larvae are parasitoid, meaning they are parasites during
the larval stage.The stinger could be used either as a
defensive mechanism, it could sting any life threatening predator; or as a way
to get food through to its larvae by stinging a cockroach for example and
laying eggs on it.
Some wasps are aggressive insects. A female
wasp can sting repeatedly with venomous sting at the end of the abdomen. When a
wasp or its nest are under threat, female wasps fly and sting the prey or the
intruder. As soon as the sharp stings pierce enemy, venom is pumped into the
wound. A wasp can sting over and over again. The
venom is highly potent. Envenomation of the host results in systematic
alterations of the host's physiology. Thus the wasp uses its stinging behavior
in order to escape predation or a way to get food to its larvae, thus
increasing its fitness.
Aposematic coloration is a defense system
against predators widely used in the animal kingdom, by which potential prey
use their striking coloration to warn a possible predator that they are toxic.
Predators learn to associate aposematic coloration with the toxicity after
testing the prey. Becoming and remaining toxic is costly for individuals, due
to costs associated with the production or storage. The size of the poison
glands is in wasps is positively correlated with brightness of aposematic
coloration. Wasps with intense coloration probably have more venom to inject,
making them more dangerous for the predators. Individuals with brighter colors, indicating
more poison, can be more easily detected by a predator. The predator can assess
the risk involved in attacking the potential prey and can decide not to attack
if the prey is very dangerous.
Wasps have a lance like stinger without barbs
and they sting repeatedly (Figure 7). Only female wasps can sting. Workers
(sterile females) may sting to defend themselves and their nests. Queens
(reproductive females) generally sting only when provoked. In addition, the
queens of the solitary wasps use their sting to paralyze their prey.
Three types of reactions may occur after a wasp sting:
- Normal reactions produce pain, redness, swelling, itching and warmth around the sting site. All evidence of the sting usually disappears in several hours
- Allergic reactions can involve an entire limb or whole body. A mild reaction produces hives, itching, fatigue and feelings of anxiety. Moderate to severe reactions may also include swelling; tightness in the throat, wheezing dizziness, stomach cramps, nausea and vomiting. Severe reactions can also include swallowing or breathing difficulties, weakness and confusion. The most serious reaction is shock, impaired breathing and heart action, which can cause death in five minutes
- Toxic reactions occur when a person receives a large volume in a short period of time. Typically from multiple stings, such as when a colony of social wasps are disturbed. Toxic reactions may produce cramps, headache, fever, drowsiness, and in extreme causes death
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