Effects of inbreeding on morphological and life history traits of the sand cricket, Gryllus firmus

Abstract

Inbreeding depression can cause substantial decreases in trait values. For colonizing organisms, which are likely to suffer relatively high levels of inbreeding at frequent intervals, inbreeding depression could significantly influence the evolution of traits and their genetic architecture. In the present paper, I examine inbreeding depression in the cricket Gryllus firmus, an inhabitant of ephemeral habitats such as sand dunes. Two questions are addressed: (i) do some traits show high levels of inbreeding depression; and (ii) do life history traits show higher levels of inbreeding depression than morphological traits? Growth rate and fecundity show very high levels of inbreeding depression (8–16% for the former, 14% for the latter). These rates of depression could potentially have significant effects on the survival probability of newly established populations. Overall, life history traits show significantly higher inbreeding depression (5.3%) than morphological traits (0.4%).