INFLUENCE OF AGE AND DISPERSAL ON REPRODUCTIVE SUCCESS OF CLIFF SWALLOWS (PETROCHELIDON PYRRHONATA)

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Tracey N. Johnson ◽  
Karl L. Kosciuch ◽  
Patricia J. Sikes ◽  
Keith A. Arnold
Keyword(s):  
Reproductive Success ◽  
Population Level ◽  
Lifetime Reproductive Success ◽  
Short Term ◽  
Petrochelidon Pyrrhonota ◽  
Age Related ◽  
Potential Population ◽  
Males And Females ◽  
Breeding Seasons ◽  
Low Rate

Abstract We examined age-related reproductive success and the short-term consequences of dispersal by known-aged Cliff Swallows (Petrochelidon pyrrhonota) breeding in Texas from 1975–86. Clutch size increased with age in females, and males and females ≥2 yrs old fledged more young than yearlings. Sixteen percent (76/463) of birds dispersed between breeding seasons and we observed female-biased dispersal. Birds that dispersed to a different colony at age 2 produced 0.91 fewer fledglings post-dispersal compared to the previous year, and birds that dispersed at age 3 produced 0.34 more fledglings post-dispersal compared to the previous year; females experienced greater benefits than males when they dispersed at age 3 yrs. Younger dispersers incur short-term costs which might have important consequences for lifetime reproductive success for a short-lived passerine. However, potential population-level consequences from dispersal costs is likely minimal given the low rate of dispersal we observed.

scholarly journals Age-related differences in reproductive success support the selection hypothesis in a Mute Swan population

2020 ◽  
Vol 161 (4) ◽  
pp. 1185-1193
Author(s):  
Radosław Włodarczyk ◽  
Piotr Minias
Keyword(s):  
Reproductive Success ◽  
Bird Species ◽  
Population Level ◽  
Older Age ◽  
Initial Increase ◽  
Mute Swan ◽  
Short Term ◽  
Selection Hypothesis ◽  
Age Cohorts ◽  
Age Related

Abstract In many bird species, we observe age-related differences in reproductive success, which usually increases early in life and later decreases due to senescence. At the individual level, an early-life improvement in breeding performance may be associated with experience acquired during early reproductive events (experience hypothesis). At the population level, higher average reproductive success of older age cohorts can result from a disappearance of low-quality individuals from the population (selection hypothesis). Here, we tested these hypotheses in a wild population of the Mute Swan Cygnus olor from central Poland. In 1996–2016, we collected information on breeding success of 150 marked individuals (70 females and 80 males; 590 breeding attempts). At the population level, there was an initial increase in reproductive success (1–5 years), followed by a plateau (5–8 years), and then by a decrease in older age classes. Both within- and between-individual age variation contributed to the linear increase in reproductive success at the population level, but the latter effect was much more apparent. Short-term breeders (≤ 2 breeding events) had significantly lower reproductive success than long-term breeders (≥ 3 breeding events) during their first two breeding attempts, providing support for selection hypothesis and disappearance of low-quality phenotypes. After exclusion of short-term breeders, a positive age-related increase in reproductive success lost significance, suggesting that under-specific condition (rapid population growth and strong human disturbance) experience may have a limited effect on reproductive success in long-lived species with strong pair bonds, such as the Mute Swan.

scholarly journals Lifetime reproductive benefits of cooperative polygamy vary for males and females in the acorn woodpecker ( Melanerpes formicivorus )

2021 ◽  
Vol 288 (1957) ◽  
pp. 20210579
Author(s):  
Sahas Barve ◽  
Christina Riehl ◽  
Eric L. Walters ◽  
Joseph Haydock ◽  
Hannah L. Dugdale ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Lifetime Reproductive Success ◽  
Cooperative Strategies ◽  
Individual Fitness ◽  
Direct Fitness ◽  
Melanerpes Formicivorus ◽  
Males And Females ◽  
Fitness Benefits ◽  
Acorn Woodpeckers ◽  
Longitudinal Dataset

Cooperative breeding strategies lead to short-term direct fitness losses when individuals forfeit or share reproduction. The direct fitness benefits of cooperative strategies are often delayed and difficult to quantify, requiring data on lifetime reproduction. Here, we use a longitudinal dataset to examine the lifetime reproductive success of cooperative polygamy in acorn woodpeckers ( Melanerpes formicivorus ), which nest as lone pairs or share reproduction with same-sex cobreeders. We found that males and females produced fewer young per successful nesting attempt when sharing reproduction. However, males nesting in duos and trios had longer reproductive lifespans, more lifetime nesting attempts and higher lifetime reproductive success than those breeding alone. For females, cobreeding in duos increased reproductive lifespan so the lifetime reproductive success of females nesting in duos was comparable to those nesting alone and higher than those nesting in trios. These results suggest that for male duos and trios, reproductive success alone may provide sufficient fitness benefits to explain the presence of cooperative polygamy, and the benefits of cobreeding as a duo in females are higher than previously assumed. Lifetime individual fitness data are crucial to reveal the full costs and benefits of cooperative polygamy.

scholarly journals Problem of Altruism

2019 ◽  
Author(s):  
Angarika Deb ◽  
Daniel Smith
Keyword(s):  
Reproductive Success ◽  
Kin Selection ◽  
Second Order ◽  
Lifetime Reproductive Success ◽  
Short Term ◽  
Order Problem ◽  
Selection Theory ◽  
Classic Problem ◽  
Psychological Altruism ◽  
Multi Level

We define two ‘problems of altruism’. The first is the classic problem of altruism, defined as the issue of how a behavior which decreases an individual’s lifetime reproductive success, while helping another individual (or individuals) increase their lifetime reproductive success, can evolve. We also define a ‘second-order problem of altruism’, where different authors have different conceptions of what does, and does not, constitute ‘altruism’, including approaches based on kin selection, multi-level selection theory, short-term altruism and psychological altruism.

scholarly journals Consequences of combining life-history traits with sex-specific differences

2020 ◽  
Author(s):  
Vandana Revathi Venkateswaran ◽  
Olivia Roth ◽  
Chaitanya S. Gokhale
Keyword(s):  
Life History ◽  
Sexual Dimorphism ◽  
Reproductive Success ◽  
Parental Investment ◽  
Life History Traits ◽  
Life History Strategies ◽  
Lifetime Reproductive Success ◽  
Fitness Components ◽  
Adult Sex Ratio ◽  
Males And Females

Males and females evolved distinct life-history strategies, reflected in diverse life-history traits, summarized as sexual dimorphism. Life-history traits are highly interlinked. The sex that allocates more resources towards offspring is expected to increase its life span, and this might require an efficient immune system. However, the other sex might allocate its resources towards ornamentation, and this might have immunosuppressive effects. Activity of immune response may not be specific to the sex that produces the eggs but could correlate with the amount of parental investment given. Informed by experimental data, we designed a theoretical framework that combines multiple life-history traits. We disentangled sex-biased life-history strategies from a particular sex to include species with reversed sex-roles, and male parental investment. We computed the lifetime reproductive success from the fitness components arising from diverse sex-biased life-history traits, and observed a strong bias in adult sex ratio depending on sex-specific resource allocation towards life-history traits. Overall, our work provides a generalized method to combine various life-history traits with sex-specific differences to calculate the lifetime reproductive success. This was used to explain certain empirical observations as a consequence of sexual dimorphism in life-history traits.

scholarly journals Subthreshold laser treatment for reticular pseudodrusen secondary to age-related macular degeneration

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Giuseppe Querques ◽  
Riccardo Sacconi ◽  
Francesco Gelormini ◽  
Enrico Borrelli ◽  
Francesco Prascina ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Laser Treatment ◽  
Age Related Macular Degeneration ◽  
Short Term ◽  
Treated Area ◽  
Reticular Pseudodrusen ◽  
End Point ◽  
Age Related ◽  
Subthreshold Laser

AbstractThere is a lack of treatment aimed at the regression of reticular pseudodrusen (RPD) secondary to age-related macular degeneration (AMD). The aim of this prospective, pilot study is to evaluate the safety and short-term efficacy of subthreshold laser treatment (SLT) in patients affected by RPD secondary to dry AMD (dAMD). Twenty eyes of 20 patients (mean age 78.4 ± 6.8 years) with RPD secondary to dAMD were prospectively enrolled. All patients were treated in an extrafoveal area of 1.27 mm2 using end-point management yellow subthreshold laser and followed for 3 months. Best-corrected visual acuity was 0.140 ± 0.09 LogMAR at the baseline and no changes were observed during the follow-up (p = 0.232). No significant worsening was disclosed before and after the treatment analyzing the macular sensitivity of the treated area (p = 0.152). No topical and/or systemic side effects were disclosed during the 3-month follow-up. The distribution among the RPD stages changed after the treatment (p < 0.001). In detail, in the treated area, we observed a significant increase in the number of Stage 1 RPD during the follow-up (p = 0.002), associated with a significant decrease of Stage 3 RPD (p = 0.020). Outer nuclear layer (ONL) thickness analysis showed a significant increase after the treatment associated with RPD regression (p = 0.001). End-point management SLT appears a safe treatment for RPD secondary to dAMD, showing short-term safety outcomes. Our results suggest that SLT could be effective in inducing a RPD regression in terms of RPD stage and ONL thickening.

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