02476nas a2200133   4500008004100000022001400041245009800055210006900153260001600222300001400238490000700252520200700259856007602266       1961                        eng d  a0005-795900aAggressiveness, Territoriality, and Sexual Behavior in Field Crickets (Orthoptera: Gryllidae)0 aAggressiveness Territoriality and Sexual Behavior in Field Crick  cJan-01-1961  a130 - 2230 v173 a<p>Most contacts between adult male field crickets involve aggressive behavior by one or both individuals and terminate with the obvious retreat of one individual. Aggressive behavior consists of one or more of several actions: in mild encounters there is either rearing of the forebody, lashing of the antennae, and shaking of the body, or else rearing of the hind body, kicking with the hind legs, and shaking of the body; in intense encounters, antennal lashing and rearing of the forebody are followed by spreading the mandibles, stridulating distinctively, rushing forward, sparring with the forelegs, butting with the head, and grappling, wrestling, or biting with the mandibles. A male is often flipped back or thrown sideways, but mutilation as a result of fighting is rare, and only in the most intense encounters is the winner determined by what seems to be superior strength or fighting ability. The outcomes of most encounters are determined by the relative tenacity of the two males, and the intensity of aggression exhibited is correlated with the length of the fight, continued aggressive activity developing into increasingly severe combat until one male finally retreats. Groups of adult male field crickets caged in small arenas form essentially linear dominance hierarchies which are stable for short periods of time and which can be described in terms of several characteristics: (1) each male dominates all or nearly all of his encounters with males below him in the hierarchy, (2) the total number of encounters by individual males decreases gradually toward the bottom of the hierarchy, (3) the intensity of aggression exhibited during encounters decreases more or less gradually toward the bottom of the hierarchy and the numbers of no-decision and no-aggression encounters and actively homosexual contacts increase, and (4) encounters between males which rank next to each other are usually more intense than encounters between males which are far apart in the hierarchy.</p>
  uhttp://booksandjournals.brillonline.com/content/10.1163/156853961x0004202215nas a2200241   4500008004100000245008200041210006900123260001600192520143800208653003801646653002701684653002501711653003201736653001501768100002601783700002301809700002401832700001501856700001801871700002301889700001801912856004301930       2018                        eng d00aAge-dependent variation in the terminal investment threshold in male crickets0 aAgedependent variation in the terminal investment threshold in m  cJan-02-20183 a<p>The terminal investment hypothesis proposes that decreased expectation of future reproduction (e.g., arising from a threat to survival) should precipitate increased investment in current reproduction. The level at which a cue of decreased survival is sufficient to trigger terminal investment (i.e., the terminal investment threshold) may vary according to other factors that influence expectation for future reproduction. We test whether the terminal investment threshold varies with age in male crickets, using heat-killed bacteria to simulate an immune-inducing infection. We measured calling effort (a behavior essential for mating) and hemolymph antimicrobial activity in young and old males across a gradient of increasing infection cue intensity. There was a significant interaction between the infection cue and age in their effect on calling effort, confirming the existence of a dynamic terminal investment threshold: young males reduced effort at all infection levels, whereas old males increased effort at the highest levels relative to na&iuml;ve individuals. A lack of a corresponding decrease in antibacterial activity suggests that altered reproductive effort is not traded against investment in this component of immunity. Collectively, these results support the existence of a dynamic terminal investment threshold, perhaps accounting for some of the conflicting evidence in support of terminal investment.</p>
10aAge-dependent reproductive effort10afecundity compensation10aGryllodes sigillatus10aresidual reproductive value10atrade-offs1 aDuffield, Kristin, R.1 aHampton, Kylie, J.1 aHouslay, Thomas, M.1 aHunt, John1 aRapkin, James1 aSakaluk, Scott, K.1 aSadd, Ben, M.  uhttp://doi.wiley.com/10.1111/evo.13443