'Mrs Ples' from Sterkfontein: Small Male or Large Female?

2000 ◽  
Vol 55 (172) ◽  
pp. 155 ◽  
Author(s):  
J. Francis Thackeray
Keyword(s):  
Large Female ◽  
Small Male

A tradeoff between mate-quality recognition and species recognition in male Bufo gargarizans that co-occur with Rana catesbeiana

2014 ◽  
Vol 64 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Tong Lei Yu ◽  
Michael Busam ◽  
David A. Pike
Keyword(s):  
Rana Catesbeiana ◽  
Species Recognition ◽  
Fertilization Success ◽  
Large Female ◽  
Small Male ◽  
Equal Frequency ◽  
Small Female ◽  
Mate Quality ◽  
Bufo Gargarizans ◽  
Simultaneous Choice

Typically, anuran amphibians favor larger females as mates because larger females lay more eggs; thus, males in amplexus can increase the number of eggs fertilized, and fitness. However, males may also prefer those females that were closest to the norm for their population in overlapping populations, and these individuals do not receive the benefits of enhanced fertilization success. In this study, we test how male Bufo gargarizans choose mates in the presence and absence of an invasive species, bullfrogs (Rana catesbeiana). When given a simultaneous choice between a small male and a large female toad, males discriminated between the sexes and attempted to clasp a large female. However, when one male toad was presented with a large female bullfrog and a small female toad, the males chose both with equal frequency. Therefore, male B. gargarizans appears to trade-off between species and mate-quality recognition, such that those toads co-occurring with heterospecifics do not blindly prefer mate-quality to ensure conspecific matings.

Partial migration and spawning movements of humpback chub in the Little Colorado River are better understood using data from autonomous PIT tag antennas

2021 ◽  
Author(s):  
Maria C. Dzul ◽  
William Louis Kendall ◽  
Charles B. Yackulic ◽  
Dana L Winkelman ◽  
David Randall Van Haverbeke ◽  
...  
Keyword(s):  
Life History ◽  
Life History Strategy ◽  
Life History Strategies ◽  
Large Female ◽  
Small Male ◽  
Small Female ◽  
Pit Tag ◽  
Demographic Groups ◽  
Humpback Chub ◽  
Survival And Growth

Choosing whether or not to migrate is an important life history decision for many fishes. Here we combine data from physical captures and detections on autonomous passive integrated transponder (PIT) tag antennas to study migration in an endangered fish, the humpback chub (Gila cypha). We develop hidden Markov mark-recapture models with and without antenna detections and find that the model fit without antenna detections misses a large proportion of fish and underestimates migration and survival probabilities. We then assess survival and growth differences associated with life history strategy and migration for different demographic groups (small male, small female, large male, large female). We find large differences in survival according to life history strategy, where residents had much lower over-winter survival than migrants. However, within the migratory life history strategy, survival and growth were similar for active migrants and skipped migrants for all demographic groups. We discuss some common challenges to incorporating detections from autonomous antennas into population models and demonstrate how these data can provide insight about fish movement and life history strategies.

scholarly journals Asymmetric mating behavior of isogamous budding yeast

2021 ◽  
Vol 7 (24) ◽  
pp. eabf8404
Author(s):  
Alexander Anders ◽  
Remy Colin ◽  
Alvaro Banderas ◽  
Victor Sourjik
Keyword(s):  
Mating Behavior ◽  
Budding Yeast ◽  
Selective Advantage ◽  
Large Female ◽  
Size Difference ◽  
Small Male ◽  
Mating Types ◽  
Behavioral Differences ◽  
Enhance Efficiency ◽  
Molecular Asymmetries

Anisogamy, the size difference between small male and large female gametes, is known to enable selection for sexual dimorphism and behavioral differences between sexes. Nevertheless, even isogamous species exhibit molecular asymmetries between mating types, which are known to ensure their self-incompatibility. Here, we show that different properties of the pheromones secreted by the MATa and MATα mating types of budding yeast lead to asymmetry in their behavioral responses during mating in mixed haploid populations, which resemble behavioral asymmetries between gametes in anisogamous organisms. MATa behaves as a random searcher that is stimulated in proportion to the fraction of MATα partner cells within the population, whereas MATα behaves as a short-range directional distance sensor. Mathematical modeling suggests that the observed asymmetric responses can enhance efficiency of mating and might thus provide a selective advantage. Our results demonstrate that the emergence of asymmetric mating behavior did not require anisogamy-based sexual selection.

Multiple Fertilization and Consecutive Spawning in Large American Lobsters, Homarus americanus

1986 ◽  
Vol 43 (11) ◽  
pp. 2291-2294 ◽  
Author(s):  
S. L. Waddy ◽  
D. E. Aiken
Keyword(s):  
Body Size ◽  
Carapace Length ◽  
Homarus Americanus ◽  
Large Female ◽  
Bay Of Fundy ◽  
Relative Fecundity ◽  
Logarithmic Relationship

Large female American lobsters, Homarus americanus (> 120 mm carapace length), maintained at nearshore Bay of Fundy temperatures often spawn twice without an intervening molt (consecutive spawning). Consecutive spawning occurs in two forms: successive-year (spawning in two successive summers, a molt in the first and fourth years) and alternate-year (spawning in alternate summers, a molt in the first and fifth years). In both types, females often are able to fertilize the two successive broods with the sperm from a single insemination (multiple fertilization). Twenty of 21 large females that were held for up to 13 yr displayed one of these types of consecutive spawning. Consecutive spawning and multiple fertilization enable large lobsters to spawn more frequently over the long term than their smaller counterparts. This, combined with the logarithmic relationship between body size and numbers of eggs produced, means that very large lobsters have a much greater relative fecundity than previously thought.

Myiasis in Bufo regularis caused by a Tabanid Larva

Parasitology ◽  
1924 ◽  
Vol 16 (1) ◽  
pp. 111-112
Author(s):  
Edward Hindle
Keyword(s):  
Fibrous Tissue ◽  
Dorsal Surface ◽  
Body Cavity ◽  
The Body ◽  
Careful Examination ◽  
Large Female ◽  
Considerable Time ◽  
Ventral Region ◽  
Cylindrical Structure ◽  
The Right

In December, 1922, whilst dissecting a large female example of Bufo regularis, one of my students noticed a cylindrical structure extending along the ventral region of the body-cavity. A careful examination showed that this structure consisted of an elongated sac-like diverticulum of the right lung, containing an almost full-grown specimen of a dipterous larva, which could be seen through the membraneous wall of the diverticulum. The base of the latter, in addition to its point of origin from the lung, was also connected to the dorsal surface of the liver by strands of fibrous tissue, suggesting that the growth had been in existence some considerable time in order to cause such adhesions. Posteriorly, the diverticulum hung freely in the body cavity and extended to the extreme hinder end. Its dimensions were 5·5 cm. in length, by 0·5 cm. in diameter, but tapering towards each extremity.

Demographic life history traits of reproductive natterjack toads (Bufo calamita) vary between northern and southern latitudes

2006 ◽  
Vol 27 (3) ◽  
pp. 365-375 ◽  
Author(s):  
Delfi Sanuy ◽  
Christoph Leskovar ◽  
Neus Oromi ◽  
Ulrich Sinsch
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Large Female ◽  
Breeding Period ◽  
Female Size ◽  
Data Set ◽  
Bufo Calamita ◽  
Trade Offs ◽  
Age Variation ◽  
The Cost

AbstractDemographic life history traits were investigated in three Bufo calamita populations in Germany (Rhineland-Palatinate: Urmitz, 50°N; 1998-2000) and Spain (Catalonia: Balaguer, Mas de Melons, 41°N; 2004). We used skeletochronology to estimate the age as number of lines of arrested growth in breeding adults collected during the spring breeding period (all localities) and during the summer breeding period (only Urmitz). A data set including the variables sex, age and size of 185 males and of 87 females was analyzed with respect to seven life history traits (age and size at maturity of the youngest first breeders, age variation in first breeders, longevity, potential reproductive lifespan, median lifespan, age-size relationship). Spring and summer cohorts at the German locality differed with respect to longevity and potential reproductive lifespan by one year in favour of the early breeders. The potential consequences on fitness and stability of cohorts are discussed. Latitudinal variation of life history traits was mainly limited to female natterjacks in which along a south-north gradient longevity and potential reproductive lifespan increased while size decreased. These results and a review of published information on natterjack demography suggest that lifetime number of offspring seem to be optimized by locally different trade-offs: large female size at the cost of longevity in southern populations and increased longevity at the cost of size in northern ones.

scholarly journals Reproductive suppression in female cooperatively breeding cichlids

2008 ◽  
Vol 4 (6) ◽  
pp. 606-609 ◽  
Author(s):  
Dik Heg
Keyword(s):  
Clutch Size ◽  
Group Living ◽  
Egg Laying ◽  
Alloparental Care ◽  
Large Female ◽  
Egg Mass ◽  
Small Female ◽  
Reproductive Suppression ◽  
Cooperatively Breeding ◽  
Female Subordinate

Suppression by dominants of female subordinate reproduction has been found in many vertebrate social groups, but has rarely been shown experimentally. Here experimental evidence is provided for reproductive suppression in the group-living Lake Tanganyika cichlid Neolamprologus pulcher . Within groups of three unrelated females, suppression was due to medium- and small-sized females laying less frequently compared with large females, and compared with medium females in control pairs. Clutch size and average egg mass of all females depended on body size, but not on rank. In a second step, a large female was removed from the group and a very small female was added to keep the group size constant. The medium females immediately seized the dominant breeding position in the group and started to reproduce as frequently as control pairs, whereas clutch size and egg mass did not change. These results show that female subordinate cichlids are reproductively capable, but apparently suppressed with respect to egg laying. Nevertheless, some reproduction is tolerated, possibly to ensure continued alloparental care by subordinate females.

Elevated plasma fractalkine levels are associated with higher levels of IL-6, Apo-B, LDL-C and insulin, but not with body composition in a large female twin sample

Metabolism ◽  
2013 ◽  
Vol 62 (8) ◽  
pp. 1081-1087 ◽  
Author(s):  
Liran Franco ◽  
Frances M.K. Williams ◽  
Svetlana Trofimov ◽  
Gabriela Surdulescu ◽  
Timothy Spector ◽  
...  
Keyword(s):  
Body Composition ◽  
Large Female ◽  
Elevated Plasma ◽  
Apo B

Men's and Women's Mating Preferences: Distinct Evolutionary Mechanisms?

2002 ◽  
Vol 11 (3) ◽  
pp. 88-93 ◽  
Author(s):  
Lynn Carol Miller ◽  
Anila Putcha-Bhagavatula ◽  
William C. Pedersen
Keyword(s):  
Sexual Functioning ◽  
Large Female ◽  
Detailed Knowledge ◽  
Short Term ◽  
Evolutionary Mechanisms ◽  
Men And Women ◽  
Mating Preferences ◽  
Chemical Mechanisms ◽  
Species Comparisons

Have men and women evolved sex-distinct mating preferences for short-term and long-term mating, as postulated by some evolutionary theorists? Direct tests of assumptions, consideration of confounds with gender, and examination of the same variables for both sexes suggest men and women are remarkably similar. Furthermore, cross-species comparisons indicate that humans do not evidence mating mechanisms indicative of short-term mating (e.g., large female sexual skins, large testicles). Understanding human variability in mating preferences is apt to involve more detailed knowledge of the links between these preferences and biological and chemical mechanisms associated with sexual motivation, sexual arousal, and sexual functioning.

Functional Maturity in Small Male Snow Crabs (Chionoecetes opilio)

1988 ◽  
Vol 45 (12) ◽  
pp. 2106-2109 ◽  
Author(s):  
G. P. Ennis ◽  
R. G. Hooper ◽  
D. M. Taylor
Keyword(s):  
Rapid Development ◽  
Carapace Width ◽  
Reproductive Potential ◽  
Snow Crab ◽  
Small Male ◽  
Chionoecetes Opilio ◽  
In Captivity ◽  
Breeding Migration ◽  
High Level ◽  
Snow Crabs

The mean size of male snow crabs (Chionoecetes opilio) in sexual pairs during the annual spring breeding migration to shallow water in Bonne Bay, Newfoundland, decreased from 118.6 mm carapace width (CW) in 1983 to 100.3 mm in 1987. This decrease is due to an increase in males <95 mm CW participating from 1.5% in 1983 to 32.3% in 1987. This change appears to have resulted from a reduced abundance of commercial size [Formula: see text] males due to a rapid development of an illegal fishery on this previously unfished population and, as a consequence, less competition between males for possession of females. The percentages of spermathecae containing new spermatophores for females paired with males <95 mm CW (67%) and those with males [Formula: see text] (79%) were not significantly different. We assumed that each female with new spermatophores had recently mated with the male with which it was paired. Observations on selected pairs in captivity showed that males <95 mm CW are capable of mating with both primiparous and muitiparous females. Our results indicate that small mature males can replace large males in breeding activity in a snow crab population. We conclude that in the male-only snow crab fishery in Atlantic Canada with a minimum legal size of 95 mm CW, population reproductive potential is maintained at a high level despite high exploitation rates on males [Formula: see text].

Sign in / Sign up

Export Citation Format

Share Document