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Allergic Reactions to Stinging

and Biting Insects

Arthur Helbling, Ulrich R. Müller

Insects can induce allergic reactions by stinging and biting. They Vespula (V. germanica and V. vulgaris in Europe; V. maculifrons
sting humans to defend themselves; they bite to feed. With regard and V. germanica in the United States) are called wasps in Europe
to allergies, stings by insects of the order Hymenoptera (bees, and yellow jackets in the US. They breed in the ground, in attics,
wasps, or ants) are much more important than bites, which can or in shelters. The genus Vespula is, by far, the most aggressive.
be inflicted by various insects, such as mosquitoes, horseflies, Stings occur not only near the nests but also more often while
midges, fleas, and bed bugs. Hymenoptera stings can induce victims are eating outdoors.
acute systemic allergic reactions that kill several hundred patients Most species of Dolichovespula (D. media, D. sylvestris, D.
in Europe and America every year, whereas systemic allergic saxonica in Europe; D. maculata, D. arenaria in the United States)
reactions to bites are very rare. Both stings and bites can induce look very similar to Vespula, with black and yellow stripes on
local allergic or toxic reactions. Infections are only transmitted the abdomen and only a slightly larger size. They can be distin-
by bites. guished from Vespula by the larger distance between the eyes
and the mandibles. Only D. maculata, the bald-faced hornet in
ENTOMOLOGICAL ASPECTS 1-4 the United States, is easy to distinguish from other vespids by
its mostly black abdomen. Dolichovespula build their nests in
Stinging Hymenoptera all belong to the suborder Aculeatae (Fig. tree branches or under the roofs of houses. They sting almost
43.1) with the families Apideae, Vespidae, Formicidae, and exclusively in the vicinity of their nests.
Myrmicinae. Latin and popular names in English, which partly The genus Vespa (V. crabro, the European hornet[ Fig. 43.2E];
differ in Europe and the United States, are given in Table 43.1. V. orientalis) is easy to distinguish from other vespids by its
much larger size. The European hornet was brought to America
Apidae in the late nineteenth century, whereas the Asian hornet (V.
In this family, the honeybee (Apis mellifera) (Fig. 43.2A) is velutina) has recently (2005) been introduced to the South of
clinically the most important cause of allergies. Stings occur France. The oriental hornet is present in southeastern Europe,
either in the vicinity of beehives or when the insect feels threatened Asia, and Africa.
during human activities, such as cutting flowers or walking Nevertheless, hornet stings are rare and occur almost exclu-
barefoot in the grass. Because the whole beehive survives over sively in the vicinity of nests, which are usually in hollow tree
winter, stings can occur not only in spring and summer but trunks or bird nesting-boxes.
occasionally also on warm winter days. Honeybees are brown Polistinae (P. annularis, P. exclamans, P. fuscatus, “paper wasp”
and moderately hairy. In contrast to other Hymenoptera, they in the United States; P. dominulus, P. gallicus, P. nympha, “field
usually lose their barbed sting when stinging. wasp” in Europe) live mostly in the southern United States and
Bumblebees (e.g., Bombus terrestris) are increasingly used as in the Mediterranean area of Europe, but small colonies have
pollinators in greenhouses and occasionally cause allergic sting been observed all over Europe except in the British Isles. Their
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reactions in greenhouse workers. Bumblebees are distinctly larger small nests consist only of one womb and are built in trees or
and more hairy compared with honeybees, and most species under roofs.
have distinct yellow or white bands on their abdomen (Fig. 43.2B).
Ants (Myrmicinae, Formicinae)
Vespidae In South and Central America, and in the southern states of the
The vespids are divided into the subfamilies Vespinae and United States, fire ants (Solenopsis invicta[see Fig. 43.3F]; S.
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Polistinae, which differ morphologically in the junction between richteri) are responsible for many systemic allergic sting reactions.
thorax and abdomen (Figs. 43.2C, D). Vespids are almost hairless, Fire ants build their mounds in yards, playgrounds, and fields.
and in most species, the abdomen is striped black and yellow. Occasional allergic sting reactions to Pogonomyrmex, the North
Vespids do not usually lose their sting when stinging and may American harvester ant, have been described and extremely rarely
therefore sting several times, even the same victim. Because only to the European red ant, Formica rufa. In contrast, species of
the queen survives over winter, larger populations develop only Myrmicinae, especially Myrmecia pilosula, the “jack-jumper ant,”
in summer, and most stings occur in summer and fall. The are an important cause of allergic sting reactions in southern
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subfamily Vespinae contains the three genera Vespula, Dolicho- Australia. Another group of aggressive ants are the ponerinae
vespula, and Vespa. of the genus Pachycondyla, including P. chinesis in the Far East
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