Female mobility and the mating system of the banner-tailed kangaroo rat (Dipodomys spectabilis)

Abstract

Like some species of pika {Ochotona) and tree squirrel {Tamiasciurus), the banner-tailed kangaroo rat {Dipodomys spectabilis) is a solitary, philopatric larder-hoarder that practices unisexual territoriality. Seeking to understand how this unusual combination of traits might influence the mating system, we used systematic trapping at mounds (burrows) and spool-and-line tracking to examine male and female visits to each other. Where genetic data exist, unisexual larder-hoarders such as D. spectabilis have been found to be polygynandrous. We asked whether the fact that females sometimes mate with more than 1 male is a passive side effect of imperfect mate defense by males, or whether females actively engage in behaviors that encourage multiple mating. During the nonbreeding season, adults of both sexes were rarely captured at mounds other than their own. In contrast, during the breeding season females as well as males were significantly more likely to be captured away from their home mounds, most often at mounds belonging to adults of the opposite sex. Spooland-line tracking during the breeding season confirmed these results. Consistent with the expectation that they engage in competitive mate searching, adult males visited adult females' mounds significantly more than expected by chance and without regard to age, size, or relatedness. More surprisingly, adult females exhibited similar behavior, expanding their home ranges and disproportionately visiting the mounds of large adult males during the nights preceding estrus. Increased (and apparently directed) female mobility during the days preceding estms may serve as a means of shaping the pool of competing mates and is worthy of more attention in this and other, ecologically similar species.

Space use patterns of the burrowing echimyid rodent,Clyomys laticeps

“…The differences observed in space use patterns between sexes are apparently reflecting reproductive strategy of each sex, concerning to access to females by males, and access to nests sites by females (Emlen & Oring, ). Hence, males may present larger movements and visit more than one burrow system, as observed during the spool‐and‐line tracking (including systems separated by 100 m), probably as a strategy to maximize mating opportunities, similar male strategies were also observed in D. ingens and D. spectabilis (Cooper & Randall, ; Steinwald et al, ). At the same time, females presented lower DHR and larger IU than males, being always recaptured at the same burrow system and remaining close to their burrows while foraging.…”

“…Social systems in burrowing rodents are classified according to the occurrence and extent of burrow sharing and spatial overlap between adults (Burda, Honeycutt, Begall, Locker-Grütjen, & Scharff, 2000;Ebensperger, Hurtado, Soto-Gamboa, Lacey, & Chang, 2004;Lacey, 2000;Steinwald, Swanson, Doyle, & Waser, 2013). Solitary species show burrow sharing restricted to motheroffspring or male and females during the mating periods (Burda et al, 2000;Ebensperger, 1998;Ebensperger, Sobrero, Campos, & Giannoni, 2008), leading to differences in home range size between sexes (Lacey, 2000;Lacey, Braude, & Wieczorek, 1998;Shier & Randall, 2004).…”

Spacing Behavior of a Non‐Larder‐Hoarding Tamiasciurus: A Study of Mearns's Squirrels in Xeric Coniferous Forests

“…Thus, as in other rodent species (Gipps ; Ostfeld ; Shier & Randall ; Adler ; Steinwald et al. ), variation in hoarding behavior appears to influence the spacing behavior of red and Douglas's squirrels.…”

“…But contrary to the territorial banner‐tailed kangaroo rat ( D. spectabilis ), where females expand their home ranges during breeding season to find desired males and to avoid inbreeding (Steinwald et al. ), female Mearns's squirrels did not increase home‐range sizes and distances traveled from nest during mating season. Nevertheless, higher overlap between sexes during mating season, and the fact that individuals nest communally during summer, support the idea of no territorial behavior in Mearns's squirrels (Munroe et al.…”

“…However, in deciduous forests of eastern North America, red squirrels do not rely on middens but are known to defend small scatter-hoarded caches of cones maintaining overlapping home ranges (Hamilton 1939;Layne 1954;Kemp & Keith 1970;Don 1983;Gurnell 1984). Thus, as in other rodent species (Gipps 1985;Ostfeld 1990;Shier & Randall 2004;Adler 2011;Steinwald et al 2013), variation in hoarding behavior appears to influence the spacing behavior of red and Douglas's squirrels.…”