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- Lissaker, M., et al.
(författare)
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Effects of a low oxygen environment on parental effort and filial cannibalism in the male sand goby, Pomatoschistus minutus
- 2003
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 14:3, s. 374-381
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Tidskriftsartikel (refereegranskat)abstract
- In fish, brood cycling parental males sometimes eat some or all of their eggs, a behavior termed filial cannibalism. We tested predictions of filial cannibalism models related to the cost of parental care in the male sand goby, Pomatoschistus minutus, by increasing the parental effort (fanning expenditure) through reduced levels of dissolved oxygen to 39% in an experimental group, whereas a control group had fully saturated water. Males showed both full-clutch cannibalism and partial-clutch cannibalism in both treatments. Giving the males one to three females to spawn with, we found that small clutches were completely eaten more often than were larger ones, whereas partial-clutch cannibalism was not affected by clutch size. Although treatment did not affect filial cannibalism, it did affect a male's energy state such that males in the low oxygen treatment lost more body fat, indicating a greater fanning effort. This shows that males in the low oxygen treatment allocated more energy to the present brood, potentially at the expense of future reproductive success. Our study strongly suggests that filial cannibalism in male sand gobies represents a strategic life-history decision as an investment in future reproductive success, and is not triggered by a proximate need for food necessary for the male's own survival. Furthermore, males in the low oxygen treatment built nests with larger entrances, and were less likely to rebuild their nests after destruction. Presumably, this makes fanning easier but the nest more vulnerable to predators, suggesting a trade-off between fanning and nest defense.
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- Svensson, Ola, 1971-, et al.
(författare)
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Costly courtship or dishonest display? Intensely displaying sand goby males have lower lipid content
- 2004
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 64:5, s. 1425-1429
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Tidskriftsartikel (refereegranskat)abstract
- Intensely displaying sand goby Pomatoschistus minutus males had lower lipid content, indicating that signalling increased energy expenditure, or that low condition males increased their signalling effort. Display intensity correlated positively with nest-defence and tended to correlate positively with filial cannibalism. (C) 2004 The Fisheries society of the British Isles.
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| 4. |
- Svensson, Ola, 1971-, et al.
(författare)
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Sexually selected nest-building - Pomatoschistus minutus males build smaller nest-openings in the presence of sneaker males
- 2003
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Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 16:5, s. 896-902
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Tidskriftsartikel (refereegranskat)abstract
- Both natural selection and sexual selection may act on nest-building. We tested experimentally how different regimes of egg-predation and male-male competition influence nest-building before mating, using the marine fish sand goby, Pomatoschistus minutus. Males with sneaker males present built the smallest nest-openings, smaller than males held alone or with Pomatoschistus microps males (which may predate eggs and compete over nest-sites but not compete over fertilizations). Males with visual access to other nest-building males tended also to build smaller openings than males held alone or with P. microps. Males with egg-predators present built nests with openings not differing significantly from any other treatment. Our results indicate that the small nest-openings found in the sneaker male treatment are sexually selected through protection against sneaking or by female choice. Across treatments, time span before a male started to build his nest also explained variation in nest-opening width; males starting late built larger nest-openings.
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