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Alternative Mating Tactics (alternative + mating_tactic)

Distribution by Scientific Domains

Life Sciences	100%

Selected Abstracts

Response of territorial males to the threat of sneaking in the three-spined stickleback (Gasterosteus aculeatus): a field study

JOURNAL OF ZOOLOGY, Issue 1 2003
Steven C. Le Comber
Abstract Alternative mating tactics are found in many species, and may have important implications for population genetics and speciation. The existence of such alternative mating tactics is well-documented in the three-spined stickleback Gasterosteus aculeatus, and sneaking and egg-stealing may occur in a significant proportion of matings under natural conditions. Sneaking can impose high costs on territorial males, both in terms of reduced reproductive output and caring for unrelated offspring. We ask whether territorial males adjust their behaviour in response to the risk of sneaking. In a field study of three-spined sticklebacks on the Isle of Arran, Scotland, territorial males were presented with glass bottles containing either a male, a female or neither, to address whether territorial males were more aggressive to other males in the presence of a female, and whether territorial males courted females less in the presence of another male. Behavioural observations showed that territorial males did not behave more aggressively towards rival males in the presence of a female, but did reduce their rate of courtship towards females in the presence of rival males. We conclude that territorial males adopt behavioural strategies that may reduce their risk of reproductive parasitism. [source]

On the analysis of non-linear allometries

ECOLOGICAL ENTOMOLOGY, Issue 1 2009
ROBERT J. KNELL
Abstract 1.,Non-linear allometries are those where a log,log scatterplot of trait size against body size deviates from simple linearity. These are found in many insects, including the horns of beetles, the forceps of earwigs, and the heads of certain castes of ant. 2.,Non-linear allometries are often associated with polyphenism that is itself related to behaviour: for example, the alternative mating tactics displayed by many species of beetle are widely associated with dimorphisms in horn size. 3.,This paper critically reviews the current techniques used to analyse these datasets. 4.,Recommendations include the use of scatterplots and assessment of the goodness of fit of simple linear models as an initial screen for non-linear allometry. The use of recently developed algorithms for ,segmented' regression to analyse continuous allometric relationships, and a pragmatic approach to the analysis of discontinuous relationships that recognises that there is no simple way to distinguish between morphs in some cases, and that all of the proposed methods for doing so have some drawbacks. 5.,Worked examples of the analysis of two sets of data from animals that have been the subject of controversy regarding the nature of their allometric relationships are given: further worked examples are provided as online Supporting Information. [source]

Effects of Social Structure on the Behaviour and Performance of Alternative Reproductive Phenotypes in Male Rock Shrimp, Rhynchocinetes typus

ETHOLOGY, Issue 4 2008
Stefan Dennenmoser
Males that adopt alternative mating tactics within a conditional strategy often undergo costly morphological changes when switching to the next phenotype during ontogeny. Whether costs of changing to a subsequent reproductive phenotype are outweighed by a higher mating probability may depend on the frequencies of different phenotypes in a group of competitors. Benefits and costs associated with different phenotype frequencies depend on interactions within and between alternative phenotypes, but the underlying behavioural mechanisms have rarely been studied. Herein, we used the rock shrimp Rhynchocinetes typus as a model: ontogenetic male stages of this species differ in morphological and behavioural traits that indicate alternative reproductive phenotypes. The small, subordinate, male stage (typus) develops via several intermediate stages (intermedius) to the dominant male stage (robustus): in competitive interactions the typus males usually employ the sneaking tactic, while the robustus males invariably employ the monopolizing fighter tactic. In laboratory experiments, we manipulated phenotype frequencies to examine whether there are frequency-dependent effects on searching behaviour, aggressiveness and mating probability. With increasing frequency of robustus males, the rate of aggressive interactions among them increased. Furthermore, robustus males increased walking velocity when more than one robustus male was present. In contrast, typus males did not adjust their searching or aggressive behaviour. The increase of aggressive interactions among robustus males provided more opportunities for typus males to seize a temporarily unguarded female. While typus males exploit fights among robustus males that produce mating opportunities for them, robustus males benefit from typus males, which reveal the presence of receptive females. We suggest that each phenotype benefits from the presence of the other phenotype and suffers costly interference among individuals of the same phenotype. Whether frequency-dependent effects on the mating probability of subordinates also affect their ontogenetic switchpoint should be examined in future studies. [source]