Anticipatory behaviour is the expectation of a near-future event based on information processed in the past and influences an animal's tactical decisions, particularly when there are significant fitness consequences. The grass lizard (Takydromus viridipunctatus) perches on blades of grass at night which likely reduces the probability of predation by terrestrial predators such as snakes, rodents and shrews. During twilight (starting 30 min before sunrise), they move from above the grass to within grass clumps and this is thought to afford the lizard protection while reducing detection by avian predators. Here, we examined how lizards shift their behaviour as a function of visual detectability to their primary predator, the cattle egret (Bubulcus ibis). We show that the lizards shift from their perch site during twilight at the earliest time at which egrets depart communal roosts. At the same time, visual modelling shows a dramatic increase in the detectability of the lizards to the visual system of egrets. Therefore, anticipatory behaviour in response to environmental cues acts to reduce predation risk as lizards become more conspicuous and predators become more active. Grass lizard anticipatory behaviour appears to be finely tuned by natural selection to adjust to temporal changes in predation risk.
Utendaji wa kutarajia ni matarajio ya tukio la karibu la siku zijazo kulingana na habari iliyoshughulikiwa katika siku za nyuma na huathiri maamuzi ya mbinu ya mnyama, haswa wakati kuna matokeo makubwa ya afya. Nyigu wa nyasi (Takydromus viridipuncta) huishi kwenye majani usiku, na hivyo kupunguza uwezekano wa kuathiriwa na wanyama wa kuogelea kama vile nyoka, panya na shrews. Wakati wa giza (kuanza dakika 30 kabla ya jua kuchomoza), wao kuhamia kutoka juu ya nyasi ndani ya nyasi clumps na hii ni walidhani kutoa kinga lizard wakati kupunguza kugundua na ndege predators. Katika utafiti huu, tulijaribu kuona jinsi nyigu wanavyoweza kuamua tabia zao kwa kutegemea jinsi wanavyoweza kuonekana na mnyama wao wa kwanza, nyigu anayeitwa cattle egret (Bubulus ibis). Kwa mfano, wadudu wa aina ya lizard huondoka kwenye makao yao wakati wa giza, wakati ambapo wadudu wa aina ya egret huondoka kwenye makao yao. Wakati huohuo, muundo wa kuona unaonyesha ongezeko kubwa katika kugundua kwa mbawakawa kwa mfumo wa kuona wa egrets. Kwa hiyo, tabia ya kutarajia katika kujibu ishara za mazingira hufanya kazi kupunguza hatari ya kuwinda wakati mbawakawa wanakuwa dhahiri zaidi na wawindaji wanakuwa hai zaidi. Utendaji wa kutazamia wa mbawakawa wa nyasi unaonekana kuwa umeboreshwa kwa uangalifu na uteuzi wa asili ili kukabiliana na mabadiliko ya muda katika hatari ya kuwinda.