scholarly journals Promiscuous mating in feral pigs (Sus scrofa) from Texas, USA

2010 ◽  
Vol 37 (7) ◽  
pp. 539 ◽  
Author(s):  
Johanna Delgado-Acevedo ◽  
Angeline Zamorano ◽  
Randy W. DeYoung ◽  
Tyler A. Campbell ◽  
David G. Hewitt ◽  
...  

Context Feral pigs represent a significant threat to agriculture and ecosystems and are disease reservoirs for pathogens affecting humans, livestock and other wildlife. Information on the behavioural ecology of feral pigs might increase the efficiency and effectiveness of management strategies. Aims We assessed the frequency of promiscuous mating in relation to oestrous synchrony in feral pigs from southern Texas, USA, an agroecosystem with a widespread and well established population of feral pigs. An association between multiple paternity of single litters and synchrony of oestrous may indicate alternative mating strategies, such as mate-guarding. Methods We collected gravid sows at nine sites in southern Texas during 2005–07. We used a panel of DNA microsatellite markers to estimate frequency of multiple paternity and the distribution of male mating among litters of feral pigs. Conception dates were determined by fitting average fetal crown–rump measurements within litters to expected fetal development relative to gestation time. Key results We found evidence of multiple paternity in 21 of 64 litters (33%) from seven of nine sites sampled. Synchrony of oestrous did not influence promiscuous mating, as we found multiple paternity at sites with synchronous and asynchronous oestrous. Males sired from 8 to 11 offspring at three sites where >10 litters were sampled. Mean litter size (5.4) was less than the best-fit value for the number of offspring, indicating that some males sired offspring with ≥ 2 females. Key conclusions Feral pigs in Texas appear to be promiscuous under a range of demographic conditions, unlike wild boar and feral pigs in other regions. The ecological and behavioural factors affecting multiple paternity are not clear, but may include male–male competition, harassment avoidance, genetic benefits for offspring, response to macro-habitat conditions, or selection. Implications A high incidence of sexual contact among individuals may increase the opportunity for diseases transmitted by oral or venereal routes, such as swine brucellosis and pseudorabies. In addition, fertility-control methods targeting males only are likely to be inefficient if female promiscuity is high; methods targeting females or both sexes jointly may be more effective.

Behaviour ◽  
2015 ◽  
Vol 152 (7-8) ◽  
pp. 1113-1144 ◽  
Author(s):  
Karpagam Chelliah ◽  
Raman Sukumar

Elaborate male traits with no apparent adaptive value may have evolved through female mate discrimination. Tusks are an elaborate male-only trait in the Asian elephant that could potentially influence female mate choice. We examined the effect of male body size, tusk possession and musth status on female mate choice in an Asian elephant population. Large/musth males received positive responses from oestrous females towards courtship significantly more often than did small/non-musth males. Young, tusked non-musth males attempted courtship significantly more often than their tuskless peers, and received more positive responses (though statistically insignificant) than did tuskless males. A positive response did not necessarily translate into mating because of mate-guarding by a dominant male. Female elephants appear to choose mates based primarily on traits such as musth that signal direct fertility benefits through increased sperm received than for traits such as tusks that may signal only indirect fitness benefits.


2006 ◽  
Vol 361 (1466) ◽  
pp. 319-334 ◽  
Author(s):  
Hanna Kokko ◽  
Daniel J Rankin

Two very basic ideas in sexual selection are heavily influenced by numbers of potential mates: the evolution of anisogamy, leading to sex role differentiation, and the frequency dependence of reproductive success that tends to equalize primary sex ratios. However, being explicit about the numbers of potential mates is not typical to most evolutionary theory of sexual selection. Here, we argue that this may prevent us from finding the appropriate ecological equilibria that determine the evolutionary endpoints of selection. We review both theoretical and empirical advances on how population density may influence aspects of mating systems such as intrasexual competition, female choice or resistance, and parental care. Density can have strong effects on selective pressures, whether or not there is phenotypic plasticity in individual strategies with respect to density. Mating skew may either increase or decrease with density, which may be aided or counteracted by changes in female behaviour. Switchpoints between alternative mating strategies can be density dependent, and mate encounter rates may influence mate choice (including mutual mate choice), multiple mating, female resistance to male mating attempts, mate searching, mate guarding, parental care, and the probability of divorce. Considering density-dependent selection may be essential for understanding how populations can persist at all despite sexual conflict, but simple models seem to fail to predict the diversity of observed responses in nature. This highlights the importance of considering the interaction between mating systems and population dynamics, and we strongly encourage further work in this area.


2016 ◽  
Vol 97 (2) ◽  
pp. 576-588 ◽  
Author(s):  
Lisa E. Schwanz ◽  
William B. Sherwin ◽  
Katherine Ognenovska ◽  
Eileen A. Lacey

Abstract Animal mating systems are driven by the temporal and spatial distribution of sexually receptive females. In mammals, ground-dwelling squirrels represent an ideal clade for testing predictions regarding the effects of these parameters on male reproductive strategies. While the majority of ground squirrel species have a short, highly synchronous annual breeding season that occurs immediately after females emerge from hibernation, the Mexican or Rio Grande ground squirrel ( Ictidomys parvidens ) differs markedly in having an extended mating season (2 months) and a long delay between emergence from hibernation and female receptivity (1–2 months). Both traits are expected to favor polygyny by increasing the chances that a male can secure matings with multiple females (e.g., females that come into estrus on different days). To test this prediction, we used microsatellite markers to characterize the mating system of a population of Rio Grande ground squirrels from Carlsbad, New Mexico. Our analyses indicated a high frequency of multiple paternity of litters in this population. Paternity was not related to spatial overlap between known mothers and assigned fathers, suggesting that territory defense is unlikely to be an effective male reproductive strategy in the study population. Dominance interactions among males were frequent, with heavier males typically winning dyadic interactions. Surprisingly, however, males with lower dominance scores appeared to have higher reproductive success, as did males that were active over a greater extent of the study site. Collectively, these results suggest that the mating system of the Rio Grande ground squirrel is best described as scramble competition polygyny, with the primary male reproductive strategy consisting of searching for estrous females. Similar patterns of male–male competition have been reported for a few other ground squirrel species, providing potentially important opportunities for comparative studies of the factors favoring this form of male reproductive strategy.


1988 ◽  
Vol 36 (5) ◽  
pp. 521 ◽  
Author(s):  
D Cook

One component of the reproductive success (fitness) of Onthophagus binodis Thunberg males was estimated by the number of offspring their mate produced relative to male horn and body size. O. binodis males consist of large horned and small hornless morphs. Female fecundity was significantly increased when reproducing with: (1) large horned males compared with small hornless males; (2) the horned morph compared with the hornless morph of males with similar body size. Horned males cooperating with females invest a considerable effort in providing each egg with dung. Hornless males do not appear to assist females after mating. Alternative male mating strategies are predicted under intense intrasexual competition. As hornless O. binodis males persist in large numbers alongside cooperative, mate guarding horned males, selection should favour alternative tactics by hornless males to gain reproductive opportunities.


2016 ◽  
Vol 78 (12) ◽  
pp. 1316-1325 ◽  
Author(s):  
Joyce A. Parga ◽  
Michelle L. Sauther ◽  
Frank P. Cuozzo ◽  
Ibrahim Antho Youssouf Jacky ◽  
Richard R. Lawler ◽  
...  

2013 ◽  
Vol 31 (4) ◽  
pp. 823-832 ◽  
Author(s):  
A. Derakhshan ◽  
J. Gherekhloo

Specific knowledge about the dormancy, germination, and emergence patterns of weed species aids the development of integrated management strategies. Laboratory studies were conducted to determine the effect of several environmental factors on seed germination and seedling emergence of Cyperus difformis. Germination of freshly harvested seeds was inhibited by darkness; however, when seeds were subsequently transferred to complete light they germinated readily. Our results showed that 2 wk of cold stratification overcome the light requirement for germination. Seeds of C. difformis were able to germinate over a broad range of temperatures (25/15, 30/20, 35/25, and 40/30 ºC day/night). The response of germination rate to temperature was described as a non-linear function. Based on model outputs, the base, the optimum and the ceiling temperatures were estimated as 14.81, 37.72 and 45 ºC, respectively. A temperature of 120 ºC for a 5 min was required to inhibit 50% of maximum germination. The osmotic potential and salinity required for 50% inhibition of maximum germination were -0.47 MPa and 135.57 mM, respectively. High percentage of seed germination (89%) was observed at pH=6 and decreased to 12% at alkaline medium (pH 9) pH. Seeds sown on the soil surface gave the greatest percentage of seedling emergence, and no seedlings emerged from seeds buried in soil at depths of 1 cm.


2020 ◽  
Vol 13 (1) ◽  
pp. 127
Author(s):  
Jay Mar D. Quevedo ◽  
Yuta Uchiyama ◽  
Kevin Muhamad Lukman ◽  
Ryo Kohsaka

Blue carbon ecosystem (BCE) initiatives in the Coral Triangle Region (CTR) are increasing due to their amplified recognition in mitigating global climate change. Although transdisciplinary approaches in the “blue carbon” discourse and collaborative actions are gaining momentum in the international and national arenas, more work is still needed at the local level. The study pursues how BCE initiatives permeate through the local communities in the Philippines and Indonesia, as part of CTR. Using perception surveys, the coastal residents from Busuanga, Philippines, and Karimunjawa, Indonesia were interviewed on their awareness, utilization, perceived threats, and management strategies for BCEs. Potential factors affecting residents’ perceptions were explored using multivariate regression and correlation analyses. Also, a comparative analysis was done to determine distinctions and commonalities in perceptions as influenced by site-specific scenarios. Results show that, despite respondents presenting relatively high awareness of BCE services, levels of utilization are low with 42.9–92.9% and 23.4–85.1% respondents in Busuanga and Karimunjawa, respectively, not directly utilizing BCE resources. Regression analysis showed that respondents’ occupation significantly influenced their utilization rate and observed opposite correlations in Busuanga (positive) and Karimunjawa (negative). Perceived threats are found to be driven by personal experiences—occurrence of natural disasters in Busuanga whereas discerned anthropogenic activities (i.e., land-use conversion) in Karimunjawa. Meanwhile, recognized management strategies are influenced by the strong presence of relevant agencies like non-government and people’s organizations in Busuanga and the local government in Karimunjawa. These results can be translated as useful metrics in contextualizing and/or enhancing BCE management plans specifically in strategizing advocacy campaigns and engagement of local stakeholders across the CTR.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248426
Author(s):  
Graham C. Smith ◽  
Richard Budgey

Industry-led culling of badgers has occurred in England to reduce the incidence of bovine tuberculosis in cattle for a number of years. Badger vaccination is also possible, and a move away from culling was “highly desirable” in a recent report to the UK government. Here we used an established simulation model to examine badger control option in a post-cull environment in England. These options included no control, various intermittent culling, badger vaccination and use of a vaccine combined with fertility control. The initial simulated cull led to a dramatic reduction in the number of infected badgers present, which increased slowly if there was no further badger management. All three approaches led to a further reduction in the number of infected badgers, with little to choose between the strategies. We do note that of the management strategies only vaccination on its own leads to a recovery of the badger population, but also an increase in the number of badgers that need to be vaccinated. We conclude that vaccination post-cull, appears to be particularly effective, compared to vaccination when the host population is at carrying capacity.


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