Danke für die Korrektur; ich hätte dazu schreiben müssen, dass es lediglich meine Vermutung ist. Wäre interessant zu wissen, inwiefern sich das
ganze Unterscheidet zwischen Arten, die "fließend" polymorph sind, wie die typische Camponotus und z.B. Camponotus truncatus. Letzere haben
ja ziemlich feste Kasten, wenn ich mich nicht irre.
Laut diesem Artikel gibt es bei den Arbeiterinnen von Acromyrmex echinatior eine genetischen Ursache:
https://www.pnas.org/content/100/16/9394
Es scheint aber auch hier eine Kombination aus Genen und äußeren Faktoren zu sein:
Zu Camponotus habe ich leider nichts dergleichen gefunden.[...]the genetic control of worker caste in A. echinatior may be plastic rather than hardwired. Further support for the mechanism being plastic comes from the lack of significant differences between colonies in the size-frequency distributions of their total worker populations. Even given the high mating frequencies of the queens, it might be expected that, under a hardwired system of genetic control, significant differences between colonies would emerge. However, the differences that existed between colonies were negligible, with all colonies showing approximately the same (presumably optimum) distribution. In addition, genetic factors alone cannot completely explain morphological worker caste determination, because changes in caste ratios with colony age, and possibly in response to environmental stimuli, are known to occur in Acromyrmex (27), and other polymorphic ant species (2, 36–38). A combination of genetic and environmental effects would therefore seem to be necessary.