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- Olsson, Karin H., 1979, et al.
(författare)
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Dark eyes in female sand gobies indicate readiness to spawn
- 2017
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 12:6
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Tidskriftsartikel (refereegranskat)abstract
- In animals, colorful and conspicuous ornaments enhance individual attractiveness to potential mates, but are typically tempered by natural selection for crypsis and predator protection. In species where males compete for females, this can lead to highly ornamented males competing for mating opportunities with choosy females, and vice versa. However, even where males compete for mating opportunities, females may exhibit conspicuous displays. These female displays are often poorly understood and it may be unclear whether they declare mating intent, signal intrasexual aggression or form a target for male mate preference. We examined the function of the conspicuous dark eyes that female sand gobies temporarily display during courtship by experimentally testing if males preferred to associate with females with artificially darkened eyes and if dark eyes are displayed during female aggression. By observing interactions between a male and two females freely associating in an aquarium we also investigated in which context females naturally displayed dark eyes. We found that dark eyes were more likely to be displayed by more gravid females than less gravid females and possibly ahead of spawning, but that males did not respond behaviorally to dark eyes or prefer dark-eyed females. Females behaving aggressively did not display dark eyes. We suggest that dark eyes are not a signal per se but may be an aspect of female mate choice, possibly related to vision.
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| 3. |
- Olsson, Karin H., 1979, et al.
(författare)
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Effect of sand texture on nest quality and mating success in a fish with parental care
- 2019
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 73:7
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Nest quality is an important aspect of courtship and mate choice, offering females direct benefits through offspring survival and, if it reflects male genetic quality, also indirect ones. Nest characteristics may thus affect both male mating success and reproductive success. Using the sand goby, where males build nests by covering mussel shells or stones in sand, we tested the role of nest material in male nest site choice, nest construction, and female mate choice. We examined the effect of sand texture (coarse or fine, depending on grain size) in two different settings: (A) when the male was free to choose between nest sites in different sand textures and other males were absent, and (B) when the male was denied a choice of sand texture and another male was present behind a partition. In (B), we also examined the effects of sand texture on female preference. In (A), males took up nest sites equally often in coarse and fine sand, but nests built in fine sand had greater sand cover. In (B), there was no difference in nest sand cover, but a greater number of males, and in particular males that weighed less and had been assigned coarse sand, refrained from building a nest at all. This suggests that sand texture does affect nest building in sand gobies, manifesting itself directly through nest sand cover, or indirectly through failure to build a nest. Moreover, we found that females preferred to spawn in well-covered nests regardless of sand texture. Significance statement: Nests offer eggs and offspring protection from predators and inclement weather, but building material may affect both the properties of the nest and the quality of the construction. Here, we presented male sand gobies with nest sites in either fine-grained or coarse-grained sand, assessed the sand cover of the nest, and allowed females to spawn. We found that grain size influenced the amount of sand cover on the nest and affected the fraction of males that refrained from building a nest. Female spawning decision depended on the amount of sand cover, but neither males nor females expressed a preference for sand texture. Our results show that nest material is an important but indirect aspect of mating success, which may influence habitat utilization in the wild. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
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| 4. |
- Olsson, Karin H., 1979, et al.
(författare)
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Hypoxia increases the risk of egg predation in a nest-guarding fish
- 2016
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Ingår i: Royal Society Open Science. - : The Royal Society. - 2054-5703. ; 3:8
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Tidskriftsartikel (refereegranskat)abstract
- For fish with parental care, a nest should meet both the oxygenation needs of the eggs and help protect them against predators. While a small nest opening facilitates the latter, it impedes the former and vice versa. We investigated how the presence of potential egg predators in the form of shore crabs Carcinus maenas affects nest building, egg fanning, defensive displays and filial cannibalism of egg-guarding male sand gobies Pomatoschistus minutus under two levels of dissolved oxygen. In the high oxygen treatment, males retained their nest opening size in the presence of crabs, while males in low oxygen built large nest openings both in the absence and presence of crabs, despite the fact that crabs were more likely to successfully intrude into nests with large entrances. Males in low oxygen also fanned more. In the presence of crabs males increased their defensive displays, but while males in high oxygen reduced fanning, males in low oxygen did not. Filial cannibalism was unaffected by treatment. Sand gobies thus prioritize egg ventilation over the protection afforded by small nest openings under hypoxia and adopt defensive behaviour to avert predator attention, even though this does not fully offset the threat from the egg predators.
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| 5. |
- Olsson, Karin H., 1979, et al.
(författare)
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Relative costs of courtship behaviours in nest-building sand gobies
- 2009
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Ingår i: Animal Behaviour. - : Elsevier BV. - 0003-3472 .- 1095-8282. ; 77, s. 541-546
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Tidskriftsartikel (refereegranskat)abstract
- Courting males often use multiple signals to advertise their quality to females. Assuming that courtship traits are energetically costly, one would expect a limit to the overall courtship effort of an individual and that a high courtship effort takes its toll on individual condition. We tested this experimentally using a small marine fish, the sand goby, Pomatoschistus minutus, whose males attract females through courtship displays and well-built nests (mussel shells covered with sand). At the end of a 5-day period of supplemental food, or repeatedly induced courtship or construction of nests (or none of these, as a control), we tested whether male display intensity, nest quality (nest cover and nest opening size) and body condition were affected. Males provided with food in excess were in significantly better condition and had significantly higher nest quality than control males. Display rate, however, was not significantly affected by feeding regime. Fish that had been manipulated to perform increased courtship or nest building did not suffer in terms of reduced condition, display rate or nest quality. However, individual fish that displayed intensely after treatment also built better-covered nests. Both of these traits are important in female choice. Moreover, fish that displayed intensely before the treatment continued to do so after treatment, a result that is compatible with signalling of genetic or phenotypic quality. Our results suggest that (1) nest cover is an honest signal of male condition, although we found no cost of nest building per se and (2) courtship display does not signal male condition.
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