| 1. |
- Alho, Jussi S., et al.
(författare)
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Increasing melanism along a latitudinal gradient in a widespread amphibian : local adaptation, ontogenic or environmental plasticity?
- 2010
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Ingår i: BMC Evolutionary Biology. - 1471-2148 .- 1471-2148. ; 10, s. 317-
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe thermal benefits of melanism in ectothermic animals are widely recognized, but relatively little is known about population differentiation in the degree of melanism along thermal gradients, and the relative contributions of genetic vs. environmental components into the level of melanism expressed. We investigated variation in the degree of melanism in the common frog (Rana temporaria; an active heliotherm thermoregulator) by comparing the degree of melanism (i) among twelve populations spanning over 1500 km long latitudinal gradient across the Scandinavian Peninsula and (ii) between two populations from latitudinal extremes subjected to larval temperature treatments in a common garden experiment.ResultsWe found that the degree of melanism increased steeply in the wild as a function of latitude. Comparison of the degree of population differentiation in melanism (PST) and neutral marker loci (FST) revealed that the PST > FST, indicating that the differences cannot be explained by random genetic drift alone. However, the latitudinal trend observed in the wild was not present in the common garden data, suggesting that the cline in nature is not attributable to direct genetic differences.ConclusionsAs straightforward local adaptation can be ruled out, the observed trend is likely to result from environment-driven phenotypic plasticity or ontogenetic plasticity coupled with population differences in age structure. In general, our results provide an example how phenotypic plasticity or even plain ontogeny can drive latitudinal clines and result in patterns perfectly matching the genetic differences expected under adaptive hypotheses.
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| 2. |
- Hjernquist, Mårten B., et al.
(författare)
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Seasonality determines patterns of growth and age structure over a geographic gradient in an ectothermic vertebrate
- 2012
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Ingår i: Oecologia. - 0029-8549 .- 1432-1939. ; 170:3, s. 641-649
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Tidskriftsartikel (refereegranskat)abstract
- Environmental variation connected with seasonality is likely to affect the evolution of life-history strategies in ectotherms, but there is no consensus as to how important life-history traits like body size are influenced by environmental variation along seasonal gradients. We compared adult body size, skeletal growth, mean age, age at first reproduction and longevity among 11 common frog ( Rana temporaria ) populations sampled along a 1,600-km-long latitudinal gradient across Scandinavia. Mean age, age at first reproduction and longevity increased linearly with decreasing growth season length. Lifetime activity (i.e. the estimated number of active days during life-time) was highest at mid-latitudes and females had on average more active days throughout their lives than males. Variation in body size was due to differences in lifetime activity among populations—individuals (especially females) were largest where they had the longest cumulative activity period—as well as to differences between populations in skeletal growth rate as determined by skeletochronological analyses. Especially, males grew faster at intermediate latitudes. While life-history trait variation was strongly associated with latitude, the direction and shape of these relationships were sex- and trait-specific. These context-dependent relationships may be the result of life-history trade-offs enforced by differences in future reproductive opportunities and time constraints among the populations. Thus, seasonality appears to be an important environmental factor shaping life-history trait variation in common frogs.
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| 3. |
- Jönsson, K. Ingemar, 1959-, et al.
(författare)
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Sexual patterns of prebreeding energy reserves in the common frog Rana temporaria along a latitudinal gradient
- 2009
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Ingår i: Ecography. - : Wiley-Blackwell. - 0906-7590 .- 1600-0587. ; 32:5, s. 831-839
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Tidskriftsartikel (refereegranskat)abstract
- The ability to store energy is an important life history trait for organisms facing long periods without energy income, and in particular for capital breeders such as temperate zone amphibians, which rely on stored energy during reproduction. However, large scale comparative studies of energy stores in populations with different environmental constraints on energy allocation are scarce. We investigated energy storage patterns in spring (after hibernation and before reproduction) in eight common frog (Rana temporaria) populations exposed to different environmental conditions along a 1600 km latitudinal gradient across Scandinavia (range of annual activity period 3-7 months). Analyses of lean body weight (eviscerated body mass), weight of fat bodies, liver weight, and liver fat content, showed that (i) post-hibernation/pre-breeding energy stores increased with increasing latitude in both sexes, (ii) males generally had larger energy reserves than females and (iii) the difference in energy stores between sexes decreased towards the north. Larger energy reserves towards the north can serve as a buffer against less predictable and/or less benign weather conditions during the short activity period, and may also represent a risk-averse tactic connected with a more pronounced iteroparous life history. In females, the continuous and overlapping vitellogenic activity in the north may also demand more reserves in early spring. The general sexual difference could be a consequence of the fact that, at the time of our sampling, females had already invested their energy into reproduction in the given year (i.e. their eggs were already ovulated), while the males' main reproductive activities (e.g. calling, mate searching, sexual competition) occurred later in the season.
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| 4. |
- Alho, Jussi S., et al.
(författare)
-
Increasing melanism along a latitudinal gradient in a widespread amphibian : local adaptation, ontogenic or environmental plasticity?
- 2010
-
Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 10:1, s. 317-
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The thermal benefits of melanism in ectothermic animals are widely recognized, but relatively little is known about population differentiation in the degree of melanism along thermal gradients, and the relative contributions of genetic vs. environmental components into the level of melanism expressed. We investigated variation in the degree of melanism in the common frog (Rana temporaria; an active heliotherm thermoregulator) by comparing the degree of melanism (i) among twelve populations spanning over 1500 km long latitudinal gradient across the Scandinavian Peninsula and (ii) between two populations from latitudinal extremes subjected to larval temperature treatments in a common garden experiment. Results: We found that the degree of melanism increased steeply in the wild as a function of latitude. Comparison of the degree of population differentiation in melanism (P-ST) and neutral marker loci (F-ST) revealed that the P-ST >F-ST, indicating that the differences cannot be explained by random genetic drift alone. However, the latitudinal trend observed in the wild was not present in the common garden data, suggesting that the cline in nature is not attributable to direct genetic differences. Conclusions: As straightforward local adaptation can be ruled out, the observed trend is likely to result from environment-driven phenotypic plasticity or ontogenetic plasticity coupled with population differences in age structure. In general, our results provide an example how phenotypic plasticity or even plain ontogeny can drive latitudinal clines and result in patterns perfectly matching the genetic differences expected under adaptive hypotheses.
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| 5. |
- Antão, Laura H., et al.
(författare)
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Climate change reshuffles northern species within their niches
- 2022
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Ingår i: Nature Climate Change. - : Springer Science and Business Media LLC. - 1758-678X .- 1758-6798. ; 12:6, s. 587-592
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Tidskriftsartikel (refereegranskat)abstract
- Climate change is a pervasive threat to biodiversity. While range shifts are a known consequence of climate warming contributing to regional community change, less is known about how species’ positions shift within their climatic niches. Furthermore, whether the relative importance of different climatic variables prompting such shifts varies with changing climate remains unclear. Here we analysed four decades of data for 1,478 species of birds, mammals, butterflies, moths, plants and phytoplankton along a 1,200 km high latitudinal gradient. The relative importance of climatic drivers varied non-uniformly with progressing climate change. While species turnover among decades was limited, the relative position of species within their climatic niche shifted substantially. A greater proportion of species responded to climatic change at higher latitudes, where changes were stronger. These diverging climate imprints restructure a full biome, making it difficult to generalize biodiversity responses and raising concerns about ecosystem integrity in the face of accelerating climate change.
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| 6. |
- Backström, Niclas, 1969-
(författare)
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Gene Mapping in Ficedula Flycatchers
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In order to get full understanding of how evolution proceeds in natural settings it is necessary to reveal the genetic basis of the phenotypic traits that play a role for individual fitness in different environments. There are a few possible approaches, most of which stem from traditional mapping efforts in domestic animals and other model species. Here we set the stage for gene mapping in natural populations of birds by producing a large number of anchor markers of broad utility for avian genetical research and use these markers to generate a genetic map of the collared flycatcher (Ficedula albicollis). The map reveals a very high degree of synteny and gene order conservation between bird species separated by as much as 100 million years. This is encouraging for later stages of mapping procedures in natural populations since this means that there is a possibility to use the information from already characterized avian genomes to track candidate genes for detailed analysis in non-model species. One interesting aspect of the low degree of rearrangements occurring in the avian genomes is that this could play a role in the low rate of hybridization barriers formed in birds compared to for instance mammals. An analysis of Z-linked gene markers reveals relatively long-range linkage disequilibrium (LD) in collared flycatchers compared to other outbred species but still, LD seems to decay within < 50 kb indicating that > 20.000 markers would be needed to cover the genome in an association scan. A detailed scan of 74 Z-linked genes evenly distributed along the chromosome in both the collared flycatcher and the pied flycatcher (Ficedula hypoleuca) indicates that there are regions that evolve under directional selection, regions that might harbor loci of importance for adaptive divergence and/or hybrid inviability.
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| 7. |
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| 8. |
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| 9. |
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| 10. |
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| 11. |
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| 12. |
- Buechel, Séverine D., et al.
(författare)
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Variation in sexual brain size dimorphism over the breeding cycle in the three-spined stickleback
- 2019
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 222:7
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Tidskriftsartikel (refereegranskat)abstract
- Snapshot analyses have demonstrated dramatic intraspecific variation in the degree of brain sexual size dimorphism (SSD). Although brain SSDis believed to be generated by the sex-specific cognitive demands of reproduction, the relative roles of developmental and population-specific contributions to variation in brain SSD remain little studied. Using a common garden experiment, we tested for sex-specific changes in brain anatomy over the breeding cycle in three-spined stickleback (Gasterosteus aculeatus) sampled from four locations in northern Europe. We found that the male brain increased in size (ca. 24%) significantly more than the female brain towards breeding, and that the resulting brain SSD was similar (ca. 20%) for all populations over the breeding cycle. Our findings support the notion that the stickleback brain is highly plastic and changes over the breeding cycle, especially in males, likely as an adaptive response to the cognitive demands of reproduction (e.g. nest construction and parental care). The results also provide evidence to suggest that breeding-related changes in brain size may be the reason for the widely varying estimates of brain SSD across studies of this species, cautioning against interpreting brain size measurements from a single time point as fixed/static.
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| 13. |
- Cichon, M, et al.
(författare)
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Mass-dependent mass loss in breeding birds : getting the null hypothesis right
- 1999
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Ingår i: Oikos. - : JSTOR. - 0030-1299 .- 1600-0706. ; 87:1, s. 191-194
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Tidskriftsartikel (refereegranskat)abstract
- An assumption central to many tests of statistical association between two variables is the null expectation of zero association. Here, we draw attention to the fact that in many published tests of mass-dependent mass loss in breeding birds, this assumption has been violated. We show that a correct null hypothesis can be derived by using resampling methods, and analyse three data sets (two previously published) from passerine birds to illustrate the approach. Our results show, that under a correct null hypothesis, the biological interpretation of the previously published results is reversed-initially heavy birds do actually lose less mass (relative to their weight) than the initially light birds.
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| 14. |
- Eriksson, Britas Klemens, et al.
(författare)
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Habitat segregation of plate phenotypes in a rapidly expanding population of three-spined stickleback
- 2021
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Ingår i: Ecosphere. - : Wiley. - 2150-8925 .- 2150-8925. ; 12:6
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Tidskriftsartikel (refereegranskat)abstract
- Declines of large predatory fish due to overexploitation are restructuring food webs across the globe. It is now becoming evident that restoring these altered food webs requires addressing not only ecological processes, but evolutionary ones as well, because human-induced rapid evolution may in turn affect ecological dynamics. We studied the potential for niche differentiation between different plate armor phenotypes in a rapidly expanding population of a small prey fish, the three-spined stickleback (Gasterosteus aculeatus). In the central Baltic Sea, three-spined stickleback abundance has increased dramatically during the past decades. The increase in this typical mesopredator has restructured near-shore food webs, increased filamentous algal blooms, and threatens coastal biodiversity. Time-series data covering 22 years show that the increase coincides with a decline in the number of juvenile perch (Perca fluviatilis), the most abundant predator of stickleback along the coast. We investigated the distribution of different stickleback plate armor phenotypes depending on latitude, environmental conditions, predator and prey abundances, nutrients, and benthic production; and described the stomach content of the stickleback phenotypes using metabarcoding. We found two distinct lateral armor plate phenotypes of stickleback, incompletely and completely plated. The proportion of incompletely plated individuals increased with increasing benthic production and decreasing abundances of adult perch. Metabarcoding showed that the stomach content of the completely plated individuals more often contained invertebrate herbivores (amphipods) than the incompletely plated ones. Since armor plates are defense structures favored by natural selection in the presence of fish predators, the phenotype distribution suggests that a novel low-predation regime favors stickleback with less armor. Our results suggest that morphological differentiation of the three-spined stickleback has the potential to affect food web dynamics and influence the persistence and resilience of the stickleback take-over in the Baltic Sea.
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| 15. |
- Flink, Henrik, et al.
(författare)
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Examining the effects of authentic C&R on the reproductive potential of Northern pike
- 2021
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Ingår i: Fisheries Research. - : Elsevier. - 0165-7836 .- 1872-6763. ; 243
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Tidskriftsartikel (refereegranskat)abstract
- The practice within recreational fisheries to release captured fish back to the wild, known as catch-and-release (C&R), is an increasingly important strategy to protect fish stocks from overexploitation. However, C&R is a stressor and since animal reproduction is particularly sensitive to stress there is reason to suspect that such a practice induces sublethal fitness consequences. Here, we investigated whether and how C&R fishing influenced the reproductive potential in an anadromous population of Northern pike (Esox lucius). First, female pike were exposed to authentic C&R using rod-and-reel fishing in a coastal foraging habitat prior to the spawning period. Next, we observed the migration to the freshwater spawning habitat and compared both the timing of arrival and maturity stage between C&R-treated and control individuals. Finally, to evaluate effects on the quality and viability of eggs we stripped captured control and recaptured C&R-treated females, measured egg dry mass to assess nutrient content, conducted artificial fertilisations and incubated eggs in a controlled laboratory experiment. We found no evidence of C&R causing alterations in either arrival time, maturity stage, or the quality and viability of fertilised eggs. In combination, our results suggest that long-term effects of C&R-induced stress on key reproductive traits of pike, if any, are minor.
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| 16. |
- Flink, Henrik, et al.
(författare)
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Recreational fisheries selectively capture and harvest large predators
- 2024
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Ingår i: Fish and Fisheries. - : John Wiley & Sons. - 1467-2960 .- 1467-2979.
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Tidskriftsartikel (refereegranskat)abstract
- Size- and species-selective harvest inevitably alters the composition of targeted populations and communities. This can potentially harm fish stocks, ecosystem functionality, and related services, as evidenced in numerous commercial fisheries. The high popularity of rod-and-reel recreational fishing, practiced by hundreds of millions globally, raises concerns about similar deteriorating effects. Despite its prevalence, the species and size selectivity of recreational fisheries remain largely unquantified due to a lack of combined catch data and fisheries-independent surveys. This study addresses this gap by using standardised monitoring data and over 60,000 digital angling catch reports from 62 distinct fisheries. The findings demonstrate a pronounced selectivity in recreational fisheries, targeting top predators and large individuals. Catch-and-release practices reduced the overall harvest by 60% but did not substantially alter this selectivity. The strong species- and size-specific selectivity mirror patterns observed in other fisheries, emphasising the importance of managing the potential adverse effects of recreational fisheries selective mortality and overfishing.
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| 17. |
- Forsman, Anders, et al.
(författare)
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Do Scale Anomalies Cause Differential Survival in Vipera berus?
- 1994
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Ingår i: Journal of Herpetology. - 0022-1511 .- 1937-2418. ; 28:4, s. 435-440
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Tidskriftsartikel (refereegranskat)abstract
- Many snake populations contain moderate to high frequencies of individuals with ventral scale anomalies, which are often associated with duplicated or fused vertebrae and ribs and are known to impair locomotion and growth. In an attempt to test whether such anomalies may influence survival, we examined their frequency among cage-reared juvenile adders, Vipera berus, and wild-caught individuals that presumably had been exposed to natural selection. Midbody ventral scale anomalies were significantlyless frequent among snakes exposed to selection than among cage-reared juveniles in one of three populations studied, indicating that they might indeed reduce survival. Furthermorem, idbody anomalies wereless common among large than among small wild-caught individuals, although not significantly so. The association between anomalies among captive mothers and their offspring was very weak, indicating low heritability of this trait. This low heritability might explain why scale anomalies are common in adder populations in spite of the apparent selection against anomalous individuals. We also found the proportion of anomalous offspring to increase with litter size, suggesting a trade-off between number and quality of young.
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| 18. |
- Forsman, Anders, et al.
(författare)
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Phenotypic evolution of dispersal-enhancing traits in insular voles
- 2011
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 278:1703, s. 225-232
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Tidskriftsartikel (refereegranskat)abstract
- Evolutionary theory predicts that in metapopulations subject to rapid extinction-recolonization dynamics, natural selection should favour evolution of traits that enhance dispersal and recolonization ability. Metapopulations of field voles (Microtus agrestis) on islands in the Stockholm archipelago, Sweden, are characterized by frequent local extinction and recolonization of subpopulations. Here, we show that voles on the islands were larger and had longer feet than expected for their body size, compared with voles from the mainland; that body size and size-specific foot length increased with increasing geographical isolation and distance from mainland; and that the differences in body size and size-specific foot length were genetically based. These findings provide rare evidence for relatively recent (less than 1000 years) and rapid (corresponding to 100-250 darwins) evolution of traits facilitating dispersal and recolonization in island metapopulations.
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| 19. |
- Givskov Sørensen, Jesper, et al.
(författare)
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Effects of predator exposure on Hsp70 expression and survival in tadpoles of the Common Frog (Rana temporaria)
- 2011
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Ingår i: Canadian Journal of Zoology. - 0008-4301 .- 1480-3283. ; 89:12, s. 1249-1255
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Tidskriftsartikel (refereegranskat)abstract
- Predator-induced changes in prey behavior and morphology are widespread, but little is known about physiological and cellular-level responses in prey in response to predation risk. We investigated whether predator (larvae of the dragonfly Aeshna Fabricius, 1775) presence elevated the expression level of heat-shock protein 70 (Hsp70)-a commonly found response to stress-in tadpoles of the Common Frog (Rana temporaria L., 1758). In another experiment, we tested the survival of tadpoles in the presence of a free-ranging predator. Prior to this encounter, the tadpoles were exposed to either an Hsp-inducing environmental stress in the form of heat (31 degrees C) or to predator cues from a caged predator. We found no evidence for increased Hsp70 expression in tadpoles either in the presence of fed or starved predators. We did not find any effects of prior exposure to neither heat nor predator presence on survival at the end of experiment. Our results do not point to either Hsp70-mediated effect of predator-induced responses or to beneficial effects of the stress response on survival under predation risk.
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| 20. |
- Hemborg, Christer, et al.
(författare)
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A sexual conflict in collared flycatchers, Ficedula albicollis : early male moult reduces female fitness
- 1998
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 265:1409, s. 2003-2007
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Tidskriftsartikel (refereegranskat)abstract
- A sexual conflict over levels of parental care occurs in most animals with biparental care, and studies of sexual differences in levels of parental care have usually focused on its intra-annual fitness consequences. We investigated inter-annual fitness consequences of a sexual difference in timing of feather replacement (moult) in collared flycatchers (Ficedula albicollis). In this study, males overlapped reproduction and moult more often than females, they also initiated their moult at an earlier stage of breeding than females. Females mated to males with a moult-breeding overlap had significantly lowered survival chances than females mated with males initiating moult after breeding. Furthermore, females mated with moulting males risked a lowered future fecundity in terms of a delayed start to breeding in the following season. However, early moulting males achieved a similar reproductive success as males initiating moult after breeding. Likewise, male survival probability to the following breeding season did not differ between early and late moulting individuals, nor was there any evidence that males gained or lost in future mating advantages by moulting early. These results show not only that a sexual conflict over timing of moult may operate, but also that it can impose severe fitness consequences, in terms of reduced future fecundity and survival probability, upon the 'losing' sex.
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| 21. |
- Hemborg, Christer, et al.
(författare)
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Reproductive investment and moult-breeding overlap in the collared flycatcher Ficedula albicollis : an experimental approach
- 1999
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Ingår i: Annales Zoologici Fennici. - 0003-455X .- 1797-2450. ; 36:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- We manipulated brood sizes of 132 pairs of the collared flycatcher to investigate whether or not an investment in reproduction was traded against an investment and timing of the post-nuptial moult. Our manipulations did not affect the probability of moult-breeding overlap in males, and there was no effect on their moult scores at fledging time of the young. Males and young birds initiated moult earlier than females and old birds, respectively. Very few females started moulting during the period of nestling care. Reproductive success in terms of recruitment rate of fledglings was independent of parental moult stage during reproduction, which indicates that the manipulation did not induce a trade-off between moult and post-fledging care. Furthermore, the survival probability of adults was independent of brood size manipulations and their moult stage at fledging time. Thus, our brood size manipulations showed no evidence for a trade-off between reproductive and moult investments in the collared flycatcher.
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| 22. |
- Hettyey, Attila, et al.
(författare)
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Does testis weight decline towards the Subarctic? : a case study on the common frog, Rana temporaria
- 2005
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Ingår i: Die Naturwissenschaften. - 0028-1042 .- 1432-1904. ; 92:4, s. 188-192
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Tidskriftsartikel (refereegranskat)abstract
- Interpopulation comparisons of variation in resource availability and in allocation patterns along altitudinal and latitudinal gradients allow insights into the mechanisms shaping the life history of animals. Patterns of between-population differences in female life history traits have been studied intensively across a wide range of taxa, but similar investigations in males have remained scarce. To study if testis weight-a measure of reproductive investment-varies on a geographical scale in anurans, we focussed on the variation in relative testis weight (RelTW) and asymmetry in 22 populations of the common frog Rana temporaria along a 1,600-km latitudinal transect across the Scandinavian peninsula. We found that RelTW decreased towards the north. Body mass and body length both had independent positive effects on testes mass. We found evidence for directional asymmetry (DA) in testis weight with the right testis being larger than the left. The level of DA in testis weight was not related to latitude, but both body mass and testes mass had independent positive effects on asymmetry. We discuss the northwards decrease in RelTW in terms of a decreased reproductive investment as a possible consequence of harsher environmental conditions, and perhaps also, weaker sexual selection in the north than in the south.
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| 23. |
- Hettyey, A, et al.
(författare)
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Does testis weight decline towards the Subarctic? A case study on the common frog, Rana temporaria
- 2005
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Ingår i: Naturwissenschaften. - : Springer Science and Business Media LLC. - 1432-1904 .- 0028-1042. ; 92:4, s. 188-192
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Tidskriftsartikel (refereegranskat)abstract
- Interpopulation comparisons of variation in resource availability and in allocation patterns along altitudinal and latitudinal gradients allow insights into the mechanisms shaping the life history of animals. Patterns of between-population differences in female life history traits have been studied intensively across a wide range of taxa, but similar investigations in males have remained scarce. To study if testis weight - ameasure of reproductive investment - varies on a geographical scale in anurans, we focussed on the variation in relative testis weight (RelTW) and asymmetry in 22 populations of the common frog Rana temporaria along a 1,600-km latitudinal transect across the Scandinavian peninsula. We found that RelTW decreased towards the north. Body mass and body length both had independent positive effects on testes mass. We found evidence for directional asymmetry (DA) in testis weight with the right testis being larger than the left. The level of DA in testis weight was not related to latitude, but both body mass and testes mass had independent positive effects on asymmetry. We discuss the northwards decrease in RelTW in terms of a decreased reproductive investment as a possible consequence of harsher environmental conditions, and perhaps also, weaker sexual selection in the north than in the south.
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| 24. |
- Hoffmann, AA, et al.
(författare)
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Heritable variation and evolution under favourable and unfavourable conditions
- 1999
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Ingår i: Trends in Ecology & Evolution. - 0169-5347 .- 1872-8383. ; 14:3, s. 96-101
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Recension (refereegranskat)abstract
- Genetic variability in quantitative traits can change as a direct response to the environmental conditions in which they are expressed. Consequently, similar selection in different environments might not be equally effective in leading to adaptation. Several hypotheses, including recent ones that focus on the historical impact of selection on populations, predict that the expression of genetic variation will increase in unfavourable conditions. However, other hypotheses lead to the opposite prediction. Although a consensus is unlikely, recent Drosophila and bird studies suggest consistent trends for morphological traits under particular conditions.
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| 25. |
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