Systematics and ecology of the Sexguttata species group, genus Cicindela (Coleoptera: Cicindelidae) / by Michael M. Kaulbars. --

Abstract

The systematics of Cicindela sexguttata Fabricius and Cicindela patruela Dejean was studied. Various aspects of their holomorphology were considered, including: multivariate analysis of external characters, morphology of the genitalia, distribution, habitat, and life history. Colour of the exoskeleton is not a stable character in this group and is not used in taxonomic decisions. The species C. denikei Brown is a sibling species of C. sexguttata, not a subspecies as previously described. The egg and third instar larva of C. denikei are described for the first time. The larval burrow of C. denikei opens directly beneath rocks and stones, a habit unique in Cicindela. The species C. sexguttata occurs throughout Eastern North America and consists of several identifiable subpopulations which are characterized by ecophenotypic characters only, and are not recognized taxonomically. The species C. patruela consists of two subspecies, C. p. patruela and C. p. consentanea Dejean. The distributions, habitats, and life histories of C. sexguttata, C. denikei, C. p. patruela, and C. p. consentanea are described. The distribution of C. sexguttata is correlated with warm moist loamy soils. Populations of C. denikei are found on sandy silty till deposited by Lake Agassiz. Some of the variability in the populations of C. sexguttata Is accounted for by differences in dominant soil type. Climate and geographic features also account for some variabnity. The different number of mature eggs in the abdomens of adult females of C. sexguttata and C. denikei indicate that the fecundity of the two species differs. Adults of C. denikei are ambush predators that change ambush site frequently. Encounters with prey modify the behaviour of the beetles such that they remain in the vicintity of the encounter. The beetles have a defended territory that moves with them as they forage.