02215nas 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.1344301541nas a2200169   4500008004100000022001300041245011100054210006900165260001600234300000800250490000700258520098500265100001701250700002501267700002301292856005601315       1998                        eng d  a0014382000aCalling Songs of Field Crickets (Teleogryllus oceanicus) With and Without Phonotactic Parasitoid Infection0 aCalling Songs of Field Crickets Teleogryllus oceanicus With and   cJan-02-1998  a1660 v523 a<p>The field cricket Teleogryllus oceanicus has been introduced to Hawaii, where it is parasitized by an acoustically orienting parasitoid fly, Ormia ochracea. Previous work showed that call parameters from parasitized populations differ from those in unparasitized populations in a direction expected if selection by flies is occurring. Here we examined songs of males collected in the field and compare calling song characters of crickets later found to harbor parasitoid larvae with those of males free of parasitoids. The two groups differ significantly in several song characteristics, particularly the trill-like long chirp given at the beginning of each song. Males with longer long chirps containing shorter interpulse intervals are more likely to be parasitized, suggesting that the flies find such males more attractive. Depending on the traits females prefer, sexual selection may oppose natural selection in altering T. oceanicus song in parasitized populations.</p>
1 aZuk, Marlene1 aRotenberry, John, T.1 aSimmons, Leigh, W.  uhttp://www.jstor.org/stable/2410931?origin=crossref