| 1. |
- Bretman, Amanda, et al.
(författare)
-
Systematic approaches to assessing high-temperature limits to fertility in animals
- 2024
-
Ingår i: Journal of Evolutionary Biology. - 1010-061X .- 1420-9101.
-
Tidskriftsartikel (refereegranskat)abstract
- Critical thermal limits (CTLs) gauge the physiological impact of temperature on survival or critical biological function, aiding predictions of species range shifts and climatic resilience. Two recent Drosophila species studies, using similar approaches to determine temperatures that induce sterility (thermal fertility limits [TFLs]), reveal that TFLs are often lower than CTLs and that TFLs better predict both current species distributions and extinction probability. Moreover, many studies show fertility is more sensitive at less extreme temperatures than survival (thermal sensitivity of fertility [TSF]). These results present a more pessimistic outlook on the consequences of climate change. However, unlike CTLs, TFL data are limited to Drosophila, and variability in TSF methods poses challenges in predicting species responses to increasing temperature. To address these data and methodological gaps, we propose 3 standardized approaches for assessing thermal impacts on fertility. We focus on adult obligate sexual terrestrial invertebrates but also provide modifications for other animal groups and life-history stages. We first outline a gold-standard protocol for determining TFLs, focussing on the effects of short-term heat shocks and simulating more frequent extreme heat events predicted by climate models. As this approach may be difficult to apply to some organisms, we then provide a standardized TSF protocol. Finally, we provide a framework to quantify fertility loss in response to extreme heat events in nature, given the limitations in laboratory approaches. Applying these standardized approaches across many taxa, similar to CTLs, will allow robust tests of the impact of fertility loss on species responses to increasing temperatures. Graphical AbstractOverview of the systematic methods (A, C, and D) to simultaneously assay lethal limits and thermal fertility limits or (B and E) thermal sensitivity of fertility. These are most easily applied to laboratory settings but can be used for assessing the fertility of wild-caught animals that have been exposed to natural temperatures.
|
|
| 2. |
- Dougherty, Liam R., et al.
(författare)
-
A systematic map of studies testing the relationship between temperature and animal reproduction
- 2024
-
Ingår i: Ecological Solutions and Evidence. - : John Wiley & Sons. - 2688-8319. ; 5:1
-
Tidskriftsartikel (refereegranskat)abstract
- Exposure to extreme temperatures can negatively affect animal reproduction, by disrupting the ability of individuals to produce any offspring (fertility), or the number of offspring produced by fertile individuals (fecundity). This has important ecological consequences, because reproduction is the ultimate measure of population fitness: a reduction in reproductive output lowers the population growth rate and increases the extinction risk. Despite this importance, there have been no large-scale summaries of the evidence for effect of temperature on reproduction.We provide a systematic map of studies testing the relationship between temperature and animal reproduction. We systematically searched for published studies that statistically test for a direct link between temperature and animal reproduction, in terms of fertility, fecundity or indirect measures of reproductive potential (gamete and gonad traits).Overall, we collated a large and rich evidence base, with 1654 papers that met our inclusion criteria, encompassing 1191 species.The map revealed several important research gaps. Insects made up almost half of the dataset, but reptiles and amphibians were uncommon, as were non-arthropod invertebrates. Fecundity was the most common reproductive trait examined, and relatively few studies measured fertility. It was uncommon for experimental studies to test exposure of different life stages, exposure to short-term heat or cold shock, exposure to temperature fluctuations, or to independently assess male and female effects. Studies were most often published in journals focusing on entomology and pest control, ecology and evolution, aquaculture and fisheries science, and marine biology. Finally, while individuals were sampled from every continent, there was a strong sampling bias towards mid-latitudes in the Northern Hemisphere, such that the tropics and polar regions are less well sampled.This map reveals a rich literature of studies testing the relationship between temperature and animal reproduction, but also uncovers substantial missing treatment of taxa, traits, and thermal regimes. This database will provide a valuable resource for future quantitative meta-analyses, and direct future studies aiming to fill identified gaps.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Fricke, Claudia, et al.
(författare)
-
Female modulation of reproductive rate and its role in postmating prezygotic isolation in Callosobruchus maculatus.
- 2006
-
Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 20:2, s. 360-368
-
Tidskriftsartikel (refereegranskat)abstract
- Summary:1. Mechanisms that come into play after mating but prior to fertilization can prevent hybrid formation and thus promote reproductive isolation. Recent research indicates that the evolution of such barriers to gene exchange between incipient forms appears to be common and is essential for speciation.2. We aimed to test if female Bean Weevils (Callosobruchus maculatus) modulate their reproductive rate and/or remating propensity in response to mating with males with varying degrees of relatedness in a manner that limits the number of ‘hybrids’ produced. We also tested if remating with a male from a female's own population, following a first mating with a foreign male, would elevate egg production.3. Females varied their egg-production rate depending on the relatedness of their mates, but this effect was not in the predicted direction. Heterospecific C. analis males actually elicited the strongest reproductive response in females, which resulted in up to 9% higher egg production. Male relatedness did not significantly affect female propensity to remate with a second male. Further, females did not generally show a compensatory increase in reproductive rate following rematings with males from their own population.4. The mechanisms documented here do not act to limit gene flow and are costly to females, as they suffer reduced life span and egg production late in life following a high reproductive rate early in life. We suggest that sexually antagonistic coevolution within species may have caused the pattern observed.
|
|
| 6. |
- Fricke, Claudia, et al.
(författare)
-
Male age does not affect female fitness in a polyandrous beetle, Callosobruchus maculatus
- 2007
-
Ingår i: Animal Behaviour. - : Elsevier BV. - 0003-3472 .- 1095-8282. ; 74:3, s. 541-548
-
Tidskriftsartikel (refereegranskat)abstract
- Males in different taxa are likely to suffer from a reduction in the quantity and/or quality of their sperm with age. This predicts age-related direct and indirect effects on female fitness. Hence, females may be selected to avoid matings with old males, or to employ alternative mating tactics, such as polyandry, to avoid fertilization by sperm of older males. In contrast, ‘viability indicator’ models of mate choice predict female preference for old males that have proven their survival ability and signal more reliably. We used a polygamous seed beetle, Callosobruchus maculatus, to test for the effects of male age on male mating success and examine the relationship between male age and female fitness, measured as female life span, lifetime fecundity, hatching success of eggs, larval development rate and egg-to-adult survival of offspring. Furthermore, we tested the hypothesis that polyandry may protect females against low numbers of functional sperm produced by old males. We report, contrary to previous findings, that male mating success indeed decreases with male age in this species. However, mating with older males did not in any way compromise female fitness and, consequently, we found no support for the idea that polyandry helps females reduce any costs of mating with older males.
|
|
| 7. |
- Fricke, Claudia, et al.
(författare)
-
Natural selection hampers divergence of reproductive traits in a seed beetle
- 2010
-
Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 23:9, s. 1857-1867
-
Tidskriftsartikel (refereegranskat)abstract
- Speciation is thought to often result from indirect selection for reproductive isolation. This will occur when reproductive traits that cause reproductive isolation evolve (i) as a by-product of natural selection on traits with which they are genetically correlated or (ii) as an indirect result of diversifying sexual selection. Here, we use experimental evolution to study the degree of divergent evolution of reproductive traits by manipulating the intensity of natural and sexual selection in replicated selection lines of seed beetles. Following 40 generations of selection, we assayed the degree of divergent evolution of reproductive traits between replicate selection lines experiencing the same selection regime. The evolution of reproductive traits was significantly divergent across selection lines within treatments. The evolution of reproductive traits was both slower and, more importantly, significantly less divergent among lines experiencing stronger directional natural selection. This suggests that reproductive traits did not evolve as an indirect by-product of adaptation. We discuss several ways in which natural selection may hamper divergent evolution among allopatric populations.
|
|
| 8. |
|
|
| 9. |
- Fricke, Claudia, 1972-
(författare)
-
Postmating Sexual Selection and its Role in Population Divergence in Beetles
- 2006
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Speciation is the process describing the formation of new species and is at the heart of evolutionary biology. According to the biological species concept only reproductively isolated forms are regarded good species. This thesis aims at identifying evolutionary processes that cause population divergence and, ultimately, speciation. Natural and sexual selection are two major candidates driving changes in traits that could render populations reproductively incompatible. In recent years, biologists have recognized that most animal species are polygamous. Therefore, sexual selection does not end at mating but continues to include interactions between individuals after mating has occurred but before zygote formation. Male-male sperm competition and cryptic female choice are two main forms of postmating sexual selection shaping reproductive traits like behaviour. The studies presented in this thesis focus on laboratory experiments attempting to identify the role of postmating sexual selection in causing reproductive divergence across populations in beetles. The majority of studies were performed using a Bruchid beetle, Callosobruchus maculatus, a common, worldwide pest on stored leguminose seeds. I used two major methodological approaches. One approach seeks to identify the traces left by past selection among extant conspecific populations, by assessing the pattern of female reproductive responses to mating with males of decreasing relatedness. Second, I used a selection experiment to disentangle the joint effect of natural and sexual selection acting simultaneously on diverging replicated selection lines. In general, these experiments revealed that postmating sexual selection can be a powerful engine of incipient divergence between allopatric populations. Changes in traits underlying variables such as female reproductive output, female mating rate or male success in sperm competition evolved rapidly and could in some cases effectively reduce gene flow between conspecific populations. While postmating sexual selection per se can drive divergence, I found that interactions with natural selection can limit divergence in reproductive characters. Sexual selection tended to reinforce natural selection under strong directional selection. In contrast, sexual selection inflicted a reproductive load on populations under weak natural selection. Thus, the joint effects of natural and sexual selection on allopatric populations are non-trivial and should be considered in greater detail in future studies of early divergence.
|
|
| 10. |
- Fricke, Claudia, et al.
(författare)
-
Rapid adaptation to a novel host in a seed beetle (Callosobruchus maculatus) : the role of sexual selection
- 2007
-
Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 61:2, s. 440-454
-
Tidskriftsartikel (refereegranskat)abstract
- Rapid diversification is common among herbivorous insects and is often the result of host shifts, leading to the exploitation of novel food sources. This, in turn, is associated with adaptive evolution of female oviposition behavior and larval feeding biology. Although natural selection is the typical driver of such adaptation, the role of sexual selection is less clear. In theory, sexual selection can either accelerate or impede adaptation. To assess the independent effects of natural and sexual selection on the rate of adaptation, we performed a laboratory natural selection experiment in a herbivorous bruchid beetle (Callosobruchus maculatus). We established replicated selection lines where we varied natural (food type) and sexual (mating system) selection in a 2 × 2 orthogonal design, and propagated our lines for 35 generations. In half of the lines, we induced a host shift whereas the other half was kept on the ancestral host. We experimentally enforced monogamy in half of the lines, whereas the other half remained polygamous. The beetles rapidly adapted to the novel host, which primarily involved increased host acceptance by females and an accelerated rate of larval development. We also found that our mating system treatment affected the rate of adaptation, but that this effect was contingent upon food type. As beetles adapted to the novel host, sexual selection reinforced natural selection whereas populations residing close to their adaptive peak (i.e., those using their ancestral host) exhibited higher fitness in the absence of sexual selection. We discuss our findings in light of current sexual selection theory and suggest that the net evolutionary effect of reproductive competition may critically depend on natural selection. Sexual selection may commonly accelerate adaptation under directional natural selection whereas sexual selection, and the associated load brought by sexual conflict, may tend to depress population fitness under stabilizing natural selection.
|
|
