The Association Between Personality Traits,Morphological Traits and Alternative Mating Behaviour in Male Endler's Guppies,Poecilia wingei

Alternative mating behaviour, personality traits and morphological characters are predicted to be correlated. Bolder, larger and more colourful males are expected to preferentially court females, while shy, small and drab‐coloured individuals are predicted to sneak copulations. We used males of Endler's guppy, Poecilia wingei, to test this association over a long temporal period (hence including ontogenetic changes) and under two social environments (male‐biased and female‐biased). We found that personality traits (exploration, boldness, activity) of P. wingei males were highly repeatable across long time spans, but they were not correlated (formed no behavioural syndrome). Male age and social environment had no effect on any personality trait, despite their effects on alternative mating behaviour. Young males with higher activity levels were more likely to attempt sneaking. In older fish, there was an association between orange coloration, courtship and boldness, but this was not observed in young males. Our results suggest that alternative mating behaviour is more flexible than personality traits and is independent of them. Non‐colour‐based morphological traits (gonopodium length, body length, caudal straps length, dorsal fin length) were not correlated with any particular mating behaviour.     

Influence of researcher experience and fieldwork intensity on the probability of brood losses in sensitive species: The case of the Red-backed Shrike Lanius collurio

Minimizing disturbance to animals when studying them should be a major consideration in ecological research design, especially when species are known to be sensitive to disturbances. A basic method in the study of bird reproductive ecology involves nest visits, but these can adversely affect birds’ breeding success. Appropriate fieldwork procedures are therefore highly important, especially in the case of timid and sensitive species. This study aimed to assess the impact of the method of searching for nests of Red-backed Shrike Lanius collurio on the probability of these birds abandoning their broods. Our study revealed that observer experience and nest searching intensity did influence the likelihood of brood desertion by this species. Less field experience and a greater nest searching intensity caused the shrikes to abandon their nests more often. We recommend paying scrupulous attention to the behaviour of the birds when searching for nests and when looking for nests after incubation has started.     

Sexual harassment in a live-bearing fish (<Emphasis Type="Italic">Poecilia mexicana</Emphasis>): influence of population-specific male mating behaviour

We investigated male sexual behaviour and the cost of sexual harassment, as measured by the reduction of female feeding time in the presence of a male, in a cave-dwelling population of Poecilia mexicana, in which sexual harassment does not occur naturally. We asked whether the lack of sexual harassment in this population is due to low sexual activity of the males, or low feeding motivation of the females. We experimentally increased the sexual activity of males or the females feeding motivation, or we used a combination of both treatments. Female feeding time was not lower in the presence of a male than in the presence of a female after sexual deprivation of the males or food deprivation of the females. Only in the combined experiment was female feeding time lower in the presence of a large male than in the presence of a small male, indicating a weak effect of sexual harassment by large males. Virgin females did not suffer a cost of sexual harassment, indicating that sexual experience does not cause the lack of sexual harassment in cave mollies. Males from a surface population, where sexual harassment occurs, significantly reduced the feeding time of cave-dwelling females even though these males exhibited surprisingly little sexual behaviour. The sexual activity of cave mollies did not correlate with male body size in any experiment, indicating that even after sexual deprivation, small cave molly males do not switch to the alternative mating behaviour known in surface-dwelling P. mexicana, where sexual activity is correlated negatively with male body size.     

Application of kinetic-based biospecific affinity chromatographic systems to ATP-dependent enzymes: studies with yeast hexokinase

This study is concerned with the development of kinetic-based bioaffinity chromatographic systems for purification of ATP-dependent kinases, with a particular focus on the allosteric yeast hexokinase enzyme (EC 2.7.1.1). Synthesis and characterization of highly substituted N(6)-linked and S(6)-linked immobilized ATP derivatives are described using a rapid solid-phase modular approach. Evaluation of the new immobilized ATP derivatives has been carried out using model chromatographic studies with yeast hexokinase, employing specific substrate analogues (N-acetyl-D-glucosamine and suramin) to promote biospecific adsorption, in the presence and absence of citrate (a so-called allosteric activator of hexokinase activity). In this paper, successful bioaffinity chromatography systems were developed for yeast hexokinase and, as a result, interesting binding and catalytic properties of the enzyme were highlighted and explored. The overall results confirm the potential for extrapolation of the kinetic locking-on tactic, a general kinetic-based bioaffinity approach already developed for the NAD(P)(+)-dependent dehydrogenases, to ATP/ADP-dependent enzymes. However, in view of the enhancement of the intrinsic ATPase activity of hexokinase with glucosamine derivatives, and the coincidental hydrolysis of immobilized ATP to immobilized ADP, future developments necessary to support adaptation of the approach to ATP-dependent enzymes are discussed.     

Duetting in insects – does call length influence reply latency?

A meta-analysis of the duetting patterns of insect taxa that signal by bioluminescence, substrate vibration, or sound was used to test the prediction that call length by the initiating male influences the latency of reply of the female. There was a significant and positive relationship between these two measures. Although tests on the entire dataset did not consider phylogeny, when all members of one sub-family of bushcricket, the Phaneropterinae, were isolated there was a significant and positive relationship between call length and reply latency. Two explanations are suggested. First, the female must wait for the conclusion of a long and potentially variable message; there is uncertainty as to when the call has finished before she can reply. Second, is the requirement of the female to process information; a longer male call, with more information requires more processing than a brief call. The authors suggest that long reply latencies may be vulnerable to intrusion by competing mates. One defensive tactic of potential female partners is to insert a trigger pulse that indicates to the female when the long and complex call has concluded. This behaviour may be considered as acoustic mate guarding and one example is given of this behaviour.     

How parasitism affects critical patch-size in a host-parasitoid model: application to the forest tent caterpillar

Habitat structure has broad impacts on many biological systems. In particular, habitat fragmentation can increase the probability of species extinction and on the other hand it can lead to population outbreaks in response to a decline in natural enemies. An extreme consequence of fragmentation is the isolation of small regions of suitable habitat surrounded by a large region of hostile matrix. This scenario can be interpreted as a critical patch-size problem, well studied in a continuous time framework, but relatively new to discrete time models. In this paper we present an integrodifference host-parasitoid model, discrete in time and continuous in space, to study how the critical habitat-size necessary for parasitoid survival changes in response to parasitoid life history traits, such as emergence time. We show that early emerging parasitoids may be able to persist in smaller habitats than late emerging species. The model predicts that these early emerging parasitoids lead to more severe host outbreaks. We hypothesise that promoting efficient late emerging parasitoids may be key in reducing outbreak severity, an approach requiring large continuous regions of suitable habitat. We parameterise the model for the host species of the forest tent caterpillar Malacosoma disstria Hbn., a pest insect for which fragmented landscape increases the severity of outbreaks. This host is known to have several parasitoids, due to paucity of data and as a first step in the modelling we consider a single generic parasitoid. The model findings are related to observations of the forest tent caterpillar offering insight into this host-parasitoid response to habitat structure.     

Alternative reproductive tactics and status-dependent selection

The status-dependent selection model on alternative reproductivetactics predicts a single switch-point in status: usually allplayers above some status (e.g., competitive ability) shouldpractice the tactic with the higher average payoff, while thosebelow that point should make the "best of a bad job" by practicingthe alternative, lower payoff tactic. Many empirical studiesindeed show a relationship between status and tactic choice,but they do not conform to this single switch-point prediction.I modify the status-dependent selection model by consideringstatus-dependent fitness that is mediated, at least in part,by resource acquisition (e.g., status-based competition forterritories or nuptial gifts). With variation in resource quality,predicted tactic-choice distributions change: a high-statusmale may be territorial on a high-quality territory, a lowerstatus male may practice an alternative tactic, and an evenlower status male may be territorial on a low-quality territory.Tactic choice thus alternates as in many empirical studies andcan appear to be but is not actually stochastic. As the numberof theoretically predicted switch-points increases, however,mixed or mixed-conditional strategies should become more prevalent.While alternative tactics will likely usually differ in meanpayoff, viewing alternative reproductive tactics as inherently"better" or "worse" (e.g., viewing cuckoldry as "worse"—thebest of a bad job) is misleading if not tempered with awarenessthat payoff can vary greatly within tactics and overlap betweentactics.     

Temperature-dependent prey capture efficiency and foraging modes of brown trout Salmo trutta

Prey capture success and foraging mode were studied in brown trout Salmo trutta at temperatures ranging from 5.7 to 14.0° C. At low temperatures, there was a positive correlation between prey capture success and the proportion of time that the fish spent holding feeding stations. This correlation was not found at temperatures >10° C.