Comparative Homing Behaviors in Two Species of Crayfish, Fallicambarus Fodiens and Orconectes Rusticus

Abstract

Homing behaviors are seen across the animal kingdom, with the magnitude and scale of these movements varying to a great degree. Invertebrates, such as crayfish, prove to be excellent models for comparative research, with relatively simple nervous systems that have been extensively studied combined with a rich behavioral repertoire that has been well documented. Here we explore whether two crayfish species (a primary burrower and a tertiary burrower) can home to artificial burrows and if so, whether their homing abilities differ. The two species of crayfish, Orconectes rusticus and Fallicambarus fodiens, were examined for their ability to home to artificial burrows in a laboratory setting. Animals were placed in a homing arena, motivated to search by the presence of food, and subsequently return to the burrows. The movements of each individual crayfish were digitized and analyzed for changes in walking speed, velocity and heading angle relative to burrows, total distance travelled and path turning angles. Crayfish of both species successfully returned home, although F. fodiens had a higher homing success rate than O. rusticus. Detailed kinematic analysis showed that walking speeds almost doubled during homing to burrows and heading angles were significantly closer to zero than on the outward journeys for both species. Path turning angles were significantly lower for O. rusticus than for F. fodiens. These findings indicate that these species of crayfish can successfully home without the visual landmark of burrow chimneys and that the primary burrower (F. fodiens) appears to be more successful with straighter return paths. The differences in these two species to home and the underlying mechanisms of homing may be due to the differences in burrow use with primary burrowers showing more efficient homing than tertiary burrowers.

Phenotypic variability of rusty crayfish (Faxonius rusticus) at the leading edge of its riverine invasion

“…Moreover, there is little to no evidence of the influence of chela size or relative body weight on dispersal speed (Kamran & Moore, 2015). However, without knowledge of the heritability of the crayfish traits examined in this study, inference regarding the specific mechanisms in operation is still limited.…”

“…The accelerating rate of spread of rusty crayfish in the JDR, the low population densities observed within several kilometres of the upstream and downstream invasion fronts, and high physiological fitness in invasion front populations suggest that a pushed invasion excluding subdominant crayfish from higher density areas is unlikely to explain the observed trait differences. Moreover, there is little to no evidence of the influence of chela size or relative body weight on dispersal speed (Kamran & Moore, 2015). Lastly, the difference in relative weight and chela length between invasion core and front populations could also be driven by natural selection in high crayfish density core populations.…”

Development of site fidelity in the nocturnal amblypygid, Phrynus marginemaculatus

“…These differences are well documented across taxa, including arachnids (Seyfarth and Barth 1972;Seyfarth et al 1982), hymenopterans Wehner 1988, 1994), decapods (Layne et al 2003a, b;Kamran and Moore 2015), and mammals (Etienne et al 1996;Etienne and Jeffery 2004;Wallace et al 2006). In particular, animals walk slowly and their paths are more sinuous on outbound journeys while inbound paths are fast, straight, and highly directed along an integrated homing vector.…”

The role of abiotic and biotic cues in burrow habitat selection by juvenile crayfish

“…The factors regulating populations are a function of multiple interacting local and regional phenomena broadly explained by adult fecundity and mortality as well as juvenile survivorship and recruitment (Berven 1990, Murdoch 1994, Rodenhouse et al 1997. Perhaps less obvious, navigation, migration, and other movements are important factors in population regulation as they aid in detection of home ranges, optimal habitats, and mating opportunities (Kamran and Moore 2015). More specifically, success of juveniles finding and occupying critical habitat is essential for population viability; however, complex life cycles can limit successful juvenile recruitment in some species (Wilbur 1980, Berven 1990, Schmidt et al 2012.…”