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Show 420 SEXUAL SELECTION. PART Jl. times been coloured brilliantly so as to imitate other protected species inhabiting the same district. When the sexes resem?le each other and both are obscurely colou.red, there IS no doubt that they have been in a mul~1tu~~ .of cases coloured for the sake of protection. So It IS m ~orne instances when both are brightly coloured, causmg them to resemble surrounding objects such .a~ fiower~, or other protected species, or indirectly by g1vmg notice to their enemies that they are of an unpalatable nature. In many other cases in which the sexes. resemble each other and are brilliantly coloured, especially when the colours are arranged for display, we may conclude th.at they have been gained by the male sex as an attractiOn, and have been transferred to both sexes. We are more especially led to this conclusion whenever the same type of coloration prevails througho~ t a gr.oup, a~d we find that the males of some species d1ffer Widely m colour from the females, whilst both sexes ~f other species are quite alike, with intermediate gradatiOns connecting these extreme states. In the same manner as bright colours have often been partially transferred from the males to the females so it has been with the extraordinary horns of man; lamellicor~ and some other beetles. So, again, the vocal or Instrumental organs proper to the males of the Homop~era an.d Orthoptera have generally been trans.f~rred m a rudimentary, or even in a nearly perfect conditiOn to the fe~ales; yet not sufficiently perfect to be used for producmg sound. It is also an interesting fact, as bearmg .on sexual selection, that the stridulating organs of cm'tam male Orthoptera are not fully develo~ ed until the last moult; and that the colours of certam m.ale d:agon-flies are not fully developed until some httle time af~er their emergence from the pupal state, and when they are ready to breed. CHAP. XI. SUMMARY ON INSECTS. 421 Sexual selection implies that the more attractive individuals are preferred by the opposite sex; and as with insects, when the sexes differ, it is the male which, with rare exceptions, is the most ornamented and departs most from the type to which the species belongs ;-and as it is the male which searches eagerly for the female, we must suppose that the females habitually or occasionally prefer the more beautiful males, and that these have thus acquired their beauty. That in most or all the orders the females have the power of rejecting any particular male, we may safely infer from the many singular contrivances possessed by the males, such as great jaws, adhesive cushions, spines, elongated legs, &c., for seizing the female ; for these contrivances shew that there is some difficulty in the act. In the case of unions between distinct species, of which many instances have been recorded, the female must have been a consenting party. Judging from what we know of the perceptive powers and affections of various insects, there is no antecedent improbability in sexual selection having come largely into action; but we have as yet no direct evidence on this head, and some facts are opposed to the belief. Nevertheless, when we see many males pursuing the same female, we can hardly believe that the pairing is left to blind chance-that the female exerts no choice, and is not influenced by the gorgeous colours or other ornaments, with which the male alone is decorated. If we admit that the females of the Homoptera and Orthoptera appreciate the musical tones emitted by their male partners, and that the various instruments for this purpose have been perfected through sexual selection, there is little improbability in the females of other insects appreciating beauty in form or colour, and consequently in such characters having been thus gained |