F Steiniger (1937 a)
[ “Disgusting taste” and visual adaptations of some insects : feeding trials with birds]
Z wiss Zool 149: 221-257
b) Vespa vulgaris and Apis mellifica
The behaviour of birds towards stinging hymenoptera and their mimics has been treated recently by Mostler (1935) in a detailed study. Since this work shows all the essential points and my own observations differ in no real respects, a detailed presentation can be avoided. Offered worker honeybees and female wasps were normally eaten by both Magpies, the Hooded Crow and especially the Spotted Flycatcher. The latter even took up bees and wasps at the same time as mealworms were offered. Over a single day (10 hours) he consumed 18 Apis workers without harm.
The Robin, Bluethroat, Garden Warbler and Blackcap attacked the first wasp that was offered, but immediately rejected it strongly without having completely killed it. The next day the offered honeybees were still taken up in the bill only by the robin, but were not eaten. The Song Thrush immediately pecked to death the presented honeybees and wasps with ruffled feathers, left them lying for some time, and then pecked them apart and gradually ate them (trials on six successive days with a totla of 14 V.vulgaris and 8 Apis). The tits did not touch wasps or honeybees.
Whilst the behaviour of the birds towards hymenoptera varies according to individual experiences, according to Erhard (1934) dogs show a particular instinctive behaviour towards wasps that differs from that towards harmless insects.
Similarly Eltringham observed in feeding trials with a grass snake [?] “The lizard snapped up the bee
but dropped it again suddenly, as though stung, and would not look at another”. Jones (1932) fed
freshly killed wasps to north american birds in the wild, and found that the following percentages were eaten of the offerings: Polistes pallipes 25%, Vespa diabolica only 5%, Vespa maculata 25%, Apis
mellifica only 1.6% were eaten.
The Robin and Bluethroat before feeding on wasps ate syrphids without exception (each fed five on three different days). About one hour after the first wasp, hoverflies were rejected (each offered 5 at the same time as 5 V.vulgaris). The next day, each did not take the 5 syrphids offered before feeding with honeybees.
When offered randomly 3-6 times per month, the Bluethroat generally did not eat syrphids during the following five months. However, the Robin ate 4 syrphids some 12 days after the first wasp. At the same time afterwards 2 wasps were offered, but were not attacked. After about 10 minutes another 3 syrphids were placed by the two wasps, which were now also not taken by the Robin, although the Robin had not taken the wasps up in its bill at all. The next day, offered 4 V.vulgaris and 4 syrphids, two of the latter were eaten, whilst one of the wasps was pecked to death but not eaten. In further similar tests, syrphids were partly taken, partly refused: Mostler shows this in such greater detail in his studies that a more detailed treatment here is not necessary. It should be mentioned, however, that during the winter following the tests described here, more than six months after every wasp or syrphid tests had stopped, the Robin scorned the first 5 syrphids offered without tasting.
The syrphids offered belonged to the three species Syrphus ribesii, Helophilus trivittatus and Scaeva
pyrastri. All three are wasp-like, so that separate treatment according to species was unnecessary, especially so since the birds made no distinction between the three species.
From a number of feeding trials with captive birds, we chose and extended those in which the birds attacked with their bills the first examples offered of any one insect species provided. Thereby, since the bird took up the insect readily, it shows that they were not frightened off by their novel appearance (misoneismus = neophobia), nor were in any way held back from them by a cage-induced timidity. In
the cases where they immediately rejected forcibly the attacked insect, this must be attributed purely to the quality of taste (in its broadest sense) of the insect. However, if they ate the insect straight away, then we can take the opportunity of carrying out studies on the possible visual adaptations present in the relevant insect species, where one allows the birds to look for a number of examples of this species. If some of these are not paid any attention, then we can conclude that this is not because of any bad taste or neophobia, but must be because the bird overlooks the species in question.
transl Francis Gilbert