Department of Anthropobiology and Sustainable Development, Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar.
Department of Zoology and Animal Biodiversity, Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar.
Am J Primatol. 2023 Dec;85(12):e23556. doi: 10.1002/ajp.23556. Epub 2023 Oct 1.
One of the most fundamental aspects of a species' behavioral strategy is its activity budget; for primates this generally involves the allocation of available time among resting, feeding, traveling, and social behavior. Comparisons between species, populations, or individuals can reveal divergences in adaptive strategies and current stressors, and reflect responses to such diverse pressures as predation, thermoregulation, nutrition, and social needs. Further, variation across seasons is an important part of behavioral strategies to survive food scarcity; this can involve increasing or decreasing effort. We documented activity over the 24-h cycle for the cathemeral, frugivorous Eulemur fulvus and the diurnal, folivorous Propithecus diadema across 13-18 months at Tsinjoarivo, Madagascar. Their activity budgets were dominated by resting (E. fulvus: 74.1%; P. diadema: 85.2%), followed by feeding (15.8%, 12.4%), traveling (9.31%, 1.74%) and social activities (0.76%, 0.70%), respectively. The lower feeding and higher resting in P. diadema likely reflect slower gastrointestinal transit and higher reliance on microbial fermentation to extract energy from fibrous food. The two species showed opposite lean season strategies. E. fulvus increased activity, with more feeding but less travel time, consistent with a shift to less-profitable fruits, and some leaves and flowers, while increasing feeding effort to compensate ("energy maximizing"). P. diadema showed less variation across months, but the lean season still evoked reduced effort across the board (feeding, travel, and social behavior), consistent with a "time minimizing" strategy prioritizing energy conservation and microbe-assisted digestion. Understanding these divergent shifts is key to understanding natural behavior and the extent of behavioral flexibility under stressful conditions. Finally, the complex patterns of fruit availability (intra- and interannually) and the species' behavioral responses across months underscore the need to move beyond simplistic "lean/abundant season" and "fruit/leaf" dichotomies in understanding underlying energetic strategies, and species' vulnerability to habitat change.
物种行为策略最基本的方面之一是其活动预算；对于灵长类动物来说，这通常涉及在休息、进食、移动和社交行为之间分配可用时间。对物种、种群或个体之间的比较可以揭示适应策略和当前压力源的差异，并反映出对捕食、体温调节、营养和社会需求等各种压力的反应。此外，跨季节的变化是生存食物匮乏的行为策略的重要组成部分；这可能涉及增加或减少努力。我们在马达加斯加的 Tsinjoarivo 记录了夜行动物、果食性的 Eulemur fulvus 和昼行动物、食叶性的 Propithecus diadema 在 13-18 个月内 24 小时周期内的活动情况。它们的活动预算主要由休息（E. fulvus：74.1%；P. diadema：85.2%）、进食（15.8%，12.4%）、移动（9.31%，1.74%）和社交活动（0.76%，0.70%）组成。P. diadema 的进食量较低和休息时间较长可能反映了其胃肠道转运速度较慢，并且更依赖微生物发酵从纤维食物中提取能量。这两个物种表现出相反的淡季策略。E. fulvus 增加了活动，增加了进食时间，但减少了移动时间，这与转向利润较低的果实以及一些叶子和花朵一致，同时增加了进食努力以补偿（“能量最大化”）。P. diadema 各月之间的变化较小，但淡季仍导致整体努力减少（进食、移动和社交行为），这与优先考虑能量节约和微生物辅助消化的“时间最小化”策略一致。了解这些不同的转变是理解自然行为和压力条件下行为灵活性程度的关键。最后，水果供应的复杂模式（年内和年际）以及物种在各月的行为反应突出表明，需要超越简单的“淡季/旺季”和“水果/叶子”二分法来理解潜在的能量策略和物种对栖息地变化的脆弱性。
