Observations on the habits and natural surroundings of insects made during the 'Skeat expedition' to the Malay peninsula, 1899-1900 / by Nelson Annandale.
- Nelson Annandale
- Date:
- 1900
Licence: In copyright
Credit: Observations on the habits and natural surroundings of insects made during the 'Skeat expedition' to the Malay peninsula, 1899-1900 / by Nelson Annandale. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![cannot be in all cases a sexual attraction, for it is exhibited by larvsB and even by eggs ^; neither can its object always be to attract prey: that it is a warning to enemies seems hardly pro- bable, for most small animals, whether aquatic or terrestrial, are attracted rather than repelled by light. In the bacteria and in forms like Noctiluca it appears to be an adventitious result of metabolism rafher than to bring any practical gain to the organism ; among the adults of the Lampyridw it very probably acts as a sexual charm ; among the larvse of the same group its purpose may possibly be to attract prey. In the case of the aquatic form there must be some reason why the larvae should come to the surface at night and display their light on the top of the water. That purpose can hardly be to warn surface enemies not to eat them, or to scare away aerial aggressors. Much more probably the light attracts some surface or aerial prey. The fact that the light disappears when the water is disturbed also supports this view. It is not to the advantage of the larvse to attract the attention of any animal big enough to make a commotion in the pool. In three other species of Lampyrid larvse, all terrestrial,—two, which were both over an inch in length, being found crawling on the ground among bushes in Patalung, and the other seated on a cocoanut-husk under a house in Kelantan—the light, which was situated in all cases on the ventral surface of the abdomen, was steady, and neither flickered as it did in the winged forms, nor slowly disappeared without apparent cause as in the case of the aquatic larva. A small specimen which I found under the mosque at Aring, mistaking it at first sight for luminous fungus which grew there commonly, continued shining w^hen picked from the ground, but immediately became dark w^hen dropped into formol, and never shone again. Professor Poulton tells me that INorth-American ^ fire-flies lose control of their lights when placed in a cyanide-bottle, and are no longer able to extinguish them. The same is true of the Malayan winged forms, though occasionally a specimen becomes entirely dark for a few minutes when first introduced into the bottle. The aquatic larva which allowed its light to reappear after it had been in corrosive sublimate for some minutes was probably only just beginning to become affected, for corrosive penetrates hard chitin very slowly. The insect allowed itself, when once affected, to be transferred into a more pungent medium before it finally ceased to shine. Of all the manifestations of luminescence among animals there is none more curious, or, in the present state of our knowledge, more inexplicable, than the manner in which large numbers of individuals of certain fire-flies are able to display their light wfith absolute apparent simultaneity and unison and with regular intervals of darkness, under circumstances which make it impossible for all the members of the swarm to see one another. Even the power, ^ See Dubois, Bull. Soc. Zool. France, xii. 1887, p. 137. ^ Darwin makes very much the same remark with regard to the Brazilian forms, in his ‘Voyage of a Naturalist ’ (p. 30). [28]](https://iiif.wellcomecollection.org/image/b22406451_0032.jp2/full/800%2C/0/default.jpg)
