Wasps- general








Wasps are related to bees and ants. They have very narrow waists and some have stingers. Wasps can be either solitary or social. Social wasps live in colonies. They can be a variety of colours including brown, yellow, metallic blue, black and red. Parasitoid wasps are usually duller colours such as black or brown. Other wasps, usually those that sting are more brightly coloured. We are familiar with those that have black and bright yellow stripes on their bodies. Social wasps: Only the females have stingers. As with bees, these stingers are modified ovipositors but are not used by the infertile females and have developed into stingers along with venom. Wasps are able to sting multiple times. Wasps make their nests out of wood fibres which they have chewed to a pulp. Many wasps are host specific. Parasitoid wasps are generally smaller species with most chalcid wasps being only 0.5mm to 1mm but there are species called fairy wasps that are as small as 0.13mm. The largest wasps are solitary, such as the cicada killer (family Sphecidae) and the tarantula hawk (family Pompilidae); both are around 38 mm. As a rule the wasp’s size is relative to the host species it preys on. *Beneficial – Family Braconidae wasps (up to 20mm)- The female wasp will inject her eggs into moths and their eggs, beetle and fly larvae, and other insect pupae and adults. Their eggs are white and can be seen on the body of caterpillars, standing up singularly. There are some species that are specialist aphid parasitoids. Adult wasps are also honey eaters and help to pollinate plants. Species include: Apanteles, Aphidius Family Chalcididae wasps- There are thousands of species. These tiny wasps are found in a variety of dark colours including metallic copper, black and green; some have yellow markings and yellow legs. They are a parasitic wasp laying their eggs in the pupae of other insects. They are generally beneficial although there are some species which feed on plants. Family Aphelinidae- Species include: Encarsia formosa, Family Ichneumonidae- Icheumon means “tracker + footprint There are thousands of species. These wasps will parasitise the larvae and pupae of moths, butterflies, beetles and flies. Many of these wasps have a long, very skinny body which can be curled at the tip making it look a little like an upside down scorpion, with females generally having very long ovipositors. Many are host-specific, with the female locating the food plants of the targeted prey then searching for the host insect i.e. eggs, larvae or pupae. Some species lay eggs on the outside of the host, some larvae pupate within the host, others form a cocoon outside the host. Species include: Orange caterpillar wasp (Netelia product) Family Trichogramma wasp- This wasp lays its eggs inside the eggs of moths and butterflies. Pest: Citrus gall wasp (Bruchophagus fellis)

Adult size: 0.15mm-50mm

Out and about

Populations of social wasps ie.those that live in colonies, are at a peak over summer. In winter most of the wasps die off with the exception of young fertilised queens. Wasps will be around in the summer when other insects are most prevalent and tend to be less active at night and during cooler months. It is estimated that there are more than 100,000 species worldwide.

Reproduction and Life cycle

New colonies are built each spring by a fertilised queen from a previous colony. These queens will then start their own colonies. Wasp colonies are very similar to those of bees. The queen is the only one to lay eggs The rest of the colony is made up of infertile worker females and some males whose sole purpose is to mate with future queens in order to make new colonies. Many species of wasp are solitary, making individual nests for their own offspring, gathering insects as a ready food source for the young. Others will lay eggs directly in a host insect which the young will feed on.

To deter

To control

Plants to repel

Plants to attract

General attractants - Alfalfa / Angelica / Anthemis (chamomile) / Artemisia (daisy) / Artichoke / Aster / Calendular / Carrot / Caraway / Chickory / Chrysanthemum / Cinquefoil / Coriander / Crimson thyme / Dandelion/ Dill / Endive / Fennel / Feverfew / Lavender / Lemon balm / Lemon marigold / Lettuce / Lobelia / Oleander / Penny royal / Parsley / Pincushion flower / Queen Anne’s lace / Rose geranium / Rue / Statice (everlasting paper flowers) / Sunflowers / Tansy / White alyssum / White clover / White cosmos / Yarrow / Zinnia Braconidae wasps - Caraway / Coriander / Fennel / Marigolds / Oleander / White clover / Yarrows Ichneumonidae wasps - Alfalfa / Carrot / Oleander / Rue


Why they are both Beneficial & Pest
On the whole, wasps are beneficial to the farmer. Many wasps are “parasitoids”, laying their eggs in the eggs, larvae, and even adults of other insects while the host is still alive! The wasp larvae eat the other insects. Non-parasitic wasps will gather insects to take back to their nests as food for their larvae. Adults are also nectar and pollen eaters and help to pollinate plants. Some wasps are a pest to humans as they can inflict extremely painful stings and are very protective of their nests. Some wasps cause damage to plants by laying their eggs in plant tissue where the larvae hatch and then feed on the plant. The citrus gall wasp is one which directly impacts on plants. Another wasp which may have an effect on lady beetles is the dinocampus wasp. Sometimes they will supplement their diet with sugar and feed on fruit. This can cause damage to the fruit. The English and European wasps are the two species that are very aggressive and cause painful stings. The English wasp seems only to collect insects for its larvae whereas the European is not fussy and collects all sort of rubbish, particularly liking sweet foods.