EFFECTS OF INBREEDING ON MORPHOLOGICAL AND LIFE-HISTORY TRAITS OF THESAND CRICKET, GRYLLUS-FIRMUS

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 coul d significantly influence the evolution of traits and their genetic ar chitecture. In the present paper, I examine inbreeding depression in t he 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? Gro wth 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 s ignificantly higher inbreeding depression (5.3%) than morphological tr aits (0.4%).