Reproduction in the Arenicolous Lizard Uma Notata

Abstract

Specimens of the sand—dwelling lizard, Uma notata, were collected monthly, primarily in the Algodones Dunes, Imperial County, California, from July 1958 through September 1962. These animals were autopsied to determine the breeding cycle of both sexes. Most individuals reach reproductive maturity during the second summer following hatching. Adult testis volumes change markedly during the year, generally reaching maximum size in May. Males were found as potential breeders from mid—April to mid—September. Females were found with eggs (usually two) in oviducts from mid—May to the late August. Females probably lay more than one clutch per year, based on observations of egg—laying captives. The reproductive period yields slightly from year to year due, at least in part, to the amount of rainfall that occurs the preceding winter. Breeding activity in males and the emergence of juveniles are delayed following dry winters. This is attributed to a series of interactions between organisms. U. notata tests do not become reproductively active if the lizards do not obtain adequate food. Insects that live in low—growing plants (annuals) normally are used for food by these lizards. However, insects that develop on these plants can do so only if sufficient rainfall occurs in winter to produce annuals. On the other hand, the larger plants (perennials) in the dunes acquire sufficient moisture from deep in the sand to flower each year, regardless of winter rains. Consequently, insects that utilize perennials are relatively plentiful every year. Following dry winters, Uma must rely on obtaining sufficient food from these insects, which presumably are more difficult to capture by sand—dwelling lizards. Thus, breeding activity is delayed until the requisite amount of food can be acquired. The reproductive responses of Urosaurus graciosus, a lizard that lives in perennial plants on these dunes, support this explanation.

Effects of Temperature and Slope on the Sprint Speed and Stamina of the Eastern Fence Lizard, Sceloporus undulatus

“…Mayhew (1968) also reported this type of activity pattern during the summer. Because the body temperature of P. mcallii corresponds closely to substrate temperature (Norris, 1949), it is physiologically advantageous for the lizard to escape the extreme surface temperatures by retreating underground.…”

“…Based on their daily movements, P. mcallii are very active and have large home ranges compared to other sympatric lizard species of similar size (Lowe, 1954;Mayhew, 1965;Baharav, 1975;Pianka andParker, 1975, Krekorian, 1976). Phrynosoma mcallii appears to be more like Phrynosoma platyrhinos (Tanner and Krogh, 1973) and Phrynosoma cornutum (Fair and Henke, 1999) ecologically, in that it has large home ranges, whereas other species in this genus (e.g., Phrynosoma modestum and Phrynosoma solare) have small home ranges (Baharav, 1975;Pianka and Parker, 1975;Munger, 1984).…”

The life history strategy of the saxicolous desert lizard, Sauromalus obesus

“…Atretic (degenerating) follicles were observed in adult female ~obesus from late April through August ( 1978 1979 Month N n x(± 2 s. e.) Range N n x(± 2 s. e.) Range -a--a- Monthly records of seasonal changes in the number of ovarian follicles have been reported for a number of lizard species (Mayhew, 1963(Mayhew, , 1965(Mayhew, , 1966(Mayhew, a & b, 1971Goldberg, 1973Goldberg, , 1975bDuda and Koul, 1977;Droge et. al., 1982).…”

“…Lizard species in this category include Sceloporus orcutti (Mayhew, 1963), ~. graciosus (Goldberg, 1975a), S. occidentalis (Goldberg, 1973), Uma inornata (Mayhew (Mayhew, 1965), ~. notata (Mayhew, 1966a), Q. scoparia (Mayhew, 1966b), and Dipsosaurus dorsalis (Mayhew, 1971).…”

Boundary processes between a desert sand dune community and an encroaching suburban landscape

“…In arid ecosystems highly variable and unpredictable precipitation often regulates biological processes (Noy-Meir, 1973). Support for this axiom can be found 3 across a broad range of taxa and regions (Mayhew 1965(Mayhew , 1966Pianka 1970;Ballinger 1977;Whitford and Creusere 1977;Seely and Louw 1980;Dunham 1981;Abts 1987;Robinson 1990;Brown and Ernest 2002;Germano and Williams 2005). Population dynamics of desert species are thus often characterized as being regulated from the bottom-up, by resource availability mediated by annual rainfall (Brown and Ernest 2002).…”