Reproductive Cycles of Three Species of Anoline Lizards from the Isthmus of Panama

Abstract

A study of the reproductive cycle of three species of lizards, a forest form, Anolis limifrons, a forest edge species, A. tropidogaster, and a grassland species, A. auratus, was carried out in the Isthmus of Panama from November 1965 until September 1969. The collecting sites were: Pacific side for all three species, mid—Isthmus for A. limifrons and A. auratus and Caribbean side for A. limifrons. Females of all three species of all sites were reproductively active during the wet season (May through December). For A. tropidogaster and A. auratus egg production almost ceases during the dry season. In A. limifrons egg production essentially ceases at the drier Pacific site and is reduced at the other two wetter ones during the same January—to—April period. The testes of males of all three species have mature spermatozoa during the dry season but mean testis weight declines from wet season highs. The male changes occur before the corresponding ones in their females so that the cycles of the two sexes may be controlled by different factors. Lipid levels of adults from the mid—Isthmus site show high values in the late dry season and lower ones throughout much of the wet season. Precipitation, food level, temperature, photoperiod, soil and leaf litter, wind, and evaporation are considered as cues influencing the cycle. The most likely candidate for the female cycle is precipitation with certain limitations. The flexible reproductive system of A. limifrons enables it to reproduce at low rates in some areas where the other two species must cease reproduction during dry periods.

Seasonal changes in testicular and epididymal histology of the tropical lizard, Tropidurus itambere (Rodrigues, 1987), during its reproductive cycle

“…In T. itambere, the reduction of mean testis volume was associated with a drop in the frequency of males containing sperm in either the testes or epididymis (Van Sluys, 1993). A similar reduction in testis size has been associated with diminished sperm production in various tropical lizards which have continuous, year-round spermatogenesis (Daniel, 1960;Licht and Gorman, 1970;Sexton et al, 1971). In T. itambere, the reproductive period coincides with the rainy season which occurs from January to April (Van Sluys, 1993).…”

“…In tropical areas, however, Squamata exhibit a broad variety of reproductive patterns, ranging from continuous to strongly seasonal reproduction, making it difficult to identify the limiting environmental factors (Vitt, 1992;Clerke and Alford, 1993). Two main hypotheses have been advanced for these areas: 1) the lack of microhabitats with adequate moisture for egg development (Sexton et al, 1971;Andrews, 1988), and 2) the lack of food resources for reproduction and/ or development of the young (Rocha, 1992;Van Sluys, 1993;Vrcibradic and Rocha, 1998). An association of all these factors could happen (Ferreira et al, 2002) during an unfavourable season.…”

“…In contrast, temperature and photoperiod under go less variation in the tropics and the dry period is comparable to the cold of temperate zones (Tinkle, 1969;Pianka, 1970). Precipitation has been demonstrated as the main factor influencing the reproductive cycle of some lizard species (Licht and Gorman, 1970;Sexton et al, 1971;Ruibal et al, 1972). The rains are important as a regulating factor of the reproductive cycle with the…”

Avian predation upon lizards and frogs in a neotropical forest understorey

“…Four of these species were taken by birds in proportion to their relative abundance with Anolis limifrons being the most common prey. Anolis auratus, which is common in grassy open areas (Sexton et al 1971), was observed in one regurgitate but not recorded during the (forest) censuses.…”

Reproductive and fat body cycles of Tropidurus hispidus and Tropidurus semitaeniatus (Squamata, Tropiduridae) in a caatinga area of northeastern Brazil

“…Traditionally, two hypotheses are used to explain reproductive seasonality in tropical oviparous lizards: (1) the restriction of microhabitats with adequate moisture for egg development (Sexton et al 1971, Andrews 1988, and (2) the lack of food resources for reproduction, offspring development, or both, during adverse seasonality (Rocha 1992, Van Sluys 1993, Vrcibradic & Rocha 1998. Additionally, a number of studies show the influence of temperature, precipitation, and day length on the reproduction of lizards (Adolph & Porter 1993, Smith 1996, Ramírez-Bautista et al 1998.…”