scholarly journals Body size and the temporal sequence in the reproductive activity of two species of aphidophagous coccinellids exploiting the same resource

2008 ◽  
Vol 105 (3) ◽  
pp. 421-425 ◽  
Author(s):  
Alois HONEK ◽  
Anthony F.G. DIXON ◽  
Zdenka MARTINKOVA
2002 ◽  
Vol 23 (4) ◽  
pp. 495-504 ◽  
Author(s):  
Otavio Marques ◽  
Lígia Pizzatto

AbstractThe reproductive biology of the false coral snake, Oxyrhopus guibei, was studied through dissection of 496 specimens, combined with observations on captive individuals. Males mature with smaller body size than females, females attain much larger body size, and male-male combat is not expected. Clutch size ranged from 3 to 20, and was correlated with female length. Reproductive cycles in both males and females seem to be continuous, with vitellogenesis and spermatogenesis occurring throughout the year. Reproductive activity in both sexes decreased at the end of the rainy season possibly due to previous intense reproductive activity in more favorable climatic conditions. The smaller number of individuals collected at the end of the rainy season apparently occurs due to the decrease of reproductive activity of this snake.


2014 ◽  
Vol 92 (7) ◽  
pp. 643-655 ◽  
Author(s):  
M.A. Ortiz ◽  
J.M. Boretto ◽  
C. Piantoni ◽  
B.B. Álvarez ◽  
N.R. Ibargüengoytía

Herein we describe the reproductive biology of a population of the Amazon Lava Lizard (Tropidurus torquatus (Wied-Neuwied, 1820)) from Corrientes, northeastern Argentina (Wet Chaco). We describe the male and female reproductive cycles, minimum body size for adults, reproductive output, mean relative clutch mass, fat body cycles, and sexual dimorphism. Our results were compared with data on the reproductive biology of Brazilian populations of T. torquatus and congeneric species. In Corrientes, males of T. torquatus exhibited a continuous reproductive cycle, but with annual variation of testicular parameters associated with spermatogenic activity. In contrast, females were reproductive only from winter to summer (July–February), laying at least two clutches each of six eggs, on average, per reproductive season. The relative clutch mass and egg size values in Corrientes were the highest reported for the species. The annual cycle of energy storage (as fat bodies) was inversely correlated with reproductive activity in both sexes. Males differed from females in snout–vent length, head size, interlimb length, and tail length. We observed interpopulational differences in relative clutch mass, egg volume and mass, incubation period and hatching time, and the minimum body size for sexual maturity probably as a result of phenotypic plasticity or adaptation to local environmental conditions and likely both.


2020 ◽  
Vol 98 (10) ◽  
pp. 651-659
Author(s):  
Jared W.H. Connoy ◽  
Jessica A. Leivesley ◽  
Ronald J. Brooks ◽  
Jacqueline D. Litzgus ◽  
Njal Rollinson

Body size may influence ectotherm behaviour by influencing heating and cooling rates, thereby constraining the time of day that some individuals can be active. The time of day at which turtles nest, for instance, is hypothesized to vary with body size at both inter- and intra-specific levels because large individuals have greater thermal inertia, retaining preferred body temperatures for a longer period of time. We use decades of data on thousands of individual nests from Algonquin Park, Ontario, Canada, to explore how body size is associated with nesting behaviour in Painted Turtles (Chrysemys picta (Schneider, 1783); small bodied) and Snapping Turtles (Chelydra serpentina (Linnaeus, 1758); large bodied). We found that (i) between species, Painted Turtles nest earlier in the evening and at higher mean temperatures than Snapping Turtles, and (ii) within species, relatively large individuals of both species nest at cooler temperatures and that relatively larger Painted Turtles nest later in the evening compared with smaller Painted Turtles. Our data support the thermal inertia hypothesis and may help explain why turtles in general exhibit geographic clines in body size: northern environments experience more daily variation in temperature, and larger size may evolve, in part, for retention of preferred body temperature during terrestrial forays.


2004 ◽  
Vol 25 (4) ◽  
pp. 395-406 ◽  
Author(s):  
Paulo Hartmann ◽  
Marília Hartmann ◽  
Célio Haddad

AbstractWe investigated reproductive activity, courtship behavior, call structure, body size, clutch size, oviposition site, and reproductive mode of Hyla sp. (aff. ehrhardti). Males called in all months, but showed a peak of activity during the rainy season. Three pair formations were observed and courtship involved stereotyped behavioral sequences, including visual signaling. Males emitted three different vocalization types: advertisement calls, courtship calls, and a vocalization of unknown function. Females attained larger body sizes than males and deposited an average of 74.5 unpigmented eggs per clutch. Early larval stages are aquatic but restricted to water in constructed subterranean nests; subsequent to flooding of nests, exotrophic tadpoles live in ponds or streams. Courtship behavior in Hyla sp. (aff. ehrhardti) is complex and the diverse repertoire of limb movements, exhibited by males, probably provide visual stimuli to females in this nocturnal treefrog. Hyla sp. (aff. ehrhardti) belongs to the H. albomarginata group. Considering the reproductive modes in this group, the complexes of H. albosignata and of H. albofrenata can be considered more close related to each other than to the H. albomarginata complex.


1959 ◽  
Vol 36 (3) ◽  
pp. 495-500
Author(s):  
A. B. GILBERT

1. The influence of sex and body weight on the concentration of the non-protein nitrogen (N.P.N.) in the blood of Carcinus moenas was investigated. 2. Blood N.P.N. decreased with body size in both sexes until a minimum was reached at a body weight of about 35 g. Thereafter it increased with increasing body weight. 3. For body weights less than 35 g. males had higher N.P.N. values than females; above this weight male values were lower. Statistically these differences were highly significant. 4. Frequency distribution of reproductive activity with body size showed peaks which correspond with those for total ionic concentration (Gilbert, 1959a, b) and with the troughs for N.P.N. 5. Results of the present work have been discussed in relation to those reported earlier for conductivity, total O.P., chloride and sulphate (Gilbert, 1959a, b).


Author(s):  
Steven Ferguson ◽  
David Yurkowski ◽  
Justine Hudson ◽  
Tera Edkins ◽  
Cornelia Willing ◽  
...  

Identification of phenotypic characteristics in reproductively successful individuals provides important insights into the evolutionary processes that cause range shifts due to environmental change. Female beluga whales (Delphinapterus leucas) from the Baffin Bay region (BB) of the Canadian Arctic in the core area of the species’ geographic range have larger body size than their conspecifics at the southern range periphery in Hudson Bay (HB). We investigated the mechanism for this north and south divergence as it relates to reproductive activity (RA = total corpora) that combines morphometric data with ovarian corpora counted from female reproductive tracts. Based on the previous finding of reproductive senescence in older HB females, but not for BB whales, we compared RA patterns the of the two populations’ with age and body length. Female beluga whale RA increased more quickly with age (63% partial variation explained) in BB than in HB (41%). In contrast, body length in HB female beluga whale accounted for considerably more of the total variation (12 vs 1%) in RA compared to BB whales. We speculate that female HB beluga whale RA was more strongly linked with body length due to higher population density resulting in food competition that favors the energetic advantages of larger body size during seasonal food limitations. Understanding the evolutionary mechanism of how RA, and potentially fitness, varies across a species’ range will assist conservation efforts in anticipating and mitigating future challenges associated with a warming planet.


2021 ◽  
Author(s):  
Steven H. Ferguson ◽  
David J. Yurkowski ◽  
Justine M. Hudson ◽  
Tera Edkins ◽  
Cornelia Willing ◽  
...  

1997 ◽  
Vol 75 (6) ◽  
pp. 847-854 ◽  
Author(s):  
Richard Alan Sweitzer ◽  
Joel Berger

Sexual selection is a commonly cited explanation for sexual size dimorphism. We examined patterns of sexual dimorphism in North American porcupines (Erethizon dorsatum) and used data on quill impalements, injuries, and guarding behavior to examine the intrasexual component of sexual selection among male porcupines. Results indicated that porcupines were sexually dimorphic for foot-pad length, body length, and body mass because males grew more rapidly and for longer periods than females. Quill impalements, injuries, and guarding episodes were restricted predominantly to older, larger males, intimating that only the largest porcupines were reproductively active. Regression analyses suggested that size was more important than age in predicting reproductive activity among males. Also, relatively few quill impalements and guarding episodes among younger, smaller animals suggest that there is a threshold size below which male porcupines do not attempt to compete for mate access. Although our data do not directly link larger body size in males with relatively high reproductive success, they suggest that sexual dimorphism in this species is at least partly the result of the intrasexual component of sexual selection. It is also possible that females select males on the basis of quill morphology or some other indicator of male quality. Thus, our understanding of sexual dimorphism in porcupines would benefit from additional research investigating the extent to which body size and patterns of quill number or size are advantageous to male porcupines in garnering mating opportunities and enhancing fitness.


Author(s):  
Fida Nassar ◽  
Souad Hraoui-Bloquet

We studied the female reproductive cycle of a population of Ophisops elegans lizard from the herpetology collection of the Natural History Museum of the Lebanese University. Females collected during spring and summer showed vitellogenesis in their ovaries with oviposition occurring from May to July followed by a subsequent quiescent period. They produced up to two clutches. Mean clutch size was 3.2 ± 1, range 2-5 eggs. Clutch size was independent of female body size. The smallest female attaining sexual maturity had a snout vent length of 45 mm. Sexual maturity can be attained within one year of age. We found no significant difference in body size between female and male adult lizards. Seasonal variations in the reproductive activity of females were well synchronized with those of males. 


2009 ◽  
Vol 30 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Attila Hettyey ◽  
Pierre-André Crochet ◽  
Juha Merilä ◽  
Gábor Herczeg ◽  
Anssi Laurila

AbstractVariation in colouration has rarely been related to sexual selection in anuran amphibians, even though such a relationship has been proven for many other vertebrate taxa. Male and female Moor Frogs (Rana arvalis) have a cryptic brown colour pattern, but males develop a conspicuous blue nuptial colouration during the reproductive season. To investigate the possibility that colouration plays a role in sexual selection in this species, we studied the temporal variation in blue colouration, determined if body size or body temperature affected blueness and investigated if blueness of males could be related to their mating success. Results confirmed previous observations that males develop and maintain blue colouration for only a very few nights during peak reproductive activity. Colouration of males was unrelated to body size, but males exhibiting higher body temperatures were somewhat bluer than males with lower body temperatures. Further, males in amplexus had higher body temperatures than non-mated males. Finally, mating success was positively related to blueness in small males, whereas in large males no such relationship was detected. While our results align with the hypothesis that the bright blue colouration of males may be a target of sexual selection, alternative explanations are also discussed.


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