Interspecific competition leads to more long‐winged morphs in two sympatric cricket species

Abstract

Abstract Coexistence mechanisms for species competing for the same resource include resource partitioning, neutrality, microhabitat preference and trade‐off between competitive and dispersal abilities. We explored the coexistence mechanism of two species of trigonidiid crickets (Dianemobius nigrofasciatus (Orthoptera: Trigonidiidae) and Polionemobius taprobanensis (Orthoptera: Trigonidiidae)) that share the same habitat. Dianemobius nigrofasciatus is more common in areas where the ground surface is somewhat open, while P. taprobanensis is more common in more densely vegetated environments. The effects of micro‐environmental differences, similarities in competitive ability and investment in dispersal ability under interspecific competitive conditions on the coexistence of these species were examined using laboratory experiments. Both P. taprobanensis and D. nigrofasciatus performed better in vegetated environments. Although the adult emergence of D. nigrofasciatus were delayed by the presence of P. taprobanensis, the emergence rate of P. taprobanensis was not significantly affected by D. nigrofasciatus. The presence of P. taprobanensis caused a higher frequency of a long‐winged morph (macropterous) of D. nigrofasciatus. The results suggest that D. nigrofasciatus is inferior to P. taprobanensis in interspecific competition, and it, therefore, disperses (as macropterous adults) at greater rates in the presence of P. taprobanensis. Furthermore, it may be that D. nigrofasciatus has been forced to change its preferred microhabitat from vegetative habitats, which are inherently more suitable, to more open environments due to competition. These above mechanisms are thought to allow the two species to coexist in the same habitat.