Sánchez-Solano Karem G, Reynoso-Cruz José E, Guevara Roger, Morales-Mávil Jorge E, Laska Matthias, Hernández-Salazar Laura T
Lab. Biología de la Conducta, Instituto de Neuroetología, Universidad Veracruzana, Xalapa, Veracruz, Mexico.
Red de Biología Evolutiva, Instituto de Ecología A.C., Xalapa, Veracruz, Mexico.
Primates. 2022 May;63(3):293-303. doi: 10.1007/s10329-022-00984-4. Epub 2022 Mar 15.
There is extensive knowledge about the visual system and the implications of the evolution of trichromatic color vision in howler monkeys (genus Alouatta) related to food selection; however, information about the other sensory systems is limited. In this study we assessed the use of touch, sniffing, and taste in fruit evaluation by 20 adult mantled howler monkeys (Alouatta palliata) on Agaltepec Island, Mexico. During 9 months of observation, we recorded the frequency that each monkey used touch, sniffing, and taste in evaluating cryptic fruits (that remain green during their ripening process) and conspicuous fruits (with red, yellow, or orange colorations when they are ripe). Sucrose content and hardness measurements were made to establish the degree of ripeness of the fruits. We found that mantled howler monkeys used long behavioral sequences during conspicuous fruit investigations. Sniffing was used infrequently, but significantly more often in the evaluation of conspicuous-ripe and unripe fruits compared to cryptic-ripe and unripe fruits. During the evaluation of cryptic-ripe fruits, mantled howler monkeys increased the use of touch compared to evaluating cryptic-unripe fruits. We did not find significant differences in the use of taste in the evaluation of cryptic and conspicuous fruits (both ripe and unripe). Our results suggest that the non-visual senses play an essential role in fruit selection by howler monkeys, with differences in the behavioral strategy according to the fruit's conspicuity. The multimodal signals of ripe and unripe fruits allow the howler monkeys to assess their palatability before being consumed.
关于视觉系统以及吼猴（蛛猴属）中三色视觉进化在食物选择方面的影响，已有广泛的知识；然而，关于其他感官系统的信息却很有限。在本研究中，我们评估了墨西哥阿加尔泰佩克岛上20只成年鬃毛吼猴（Alouatta palliata）在评估水果时对触觉、嗅觉和味觉的运用。在9个月的观察期内，我们记录了每只猴子在评估隐秘果实（在成熟过程中保持绿色）和显眼果实（成熟时呈现红色、黄色或橙色）时使用触觉、嗅觉和味觉的频率。对果实的蔗糖含量和硬度进行了测量，以确定果实的成熟程度。我们发现，鬃毛吼猴在调查显眼果实时会使用较长的行为序列。嗅觉的使用频率较低，但与评估隐秘成熟和未成熟果实相比，在评估显眼成熟和未成熟果实时使用得更为频繁。在评估隐秘成熟果实时，鬃毛吼猴与评估隐秘未成熟果实时相比，增加了触觉的使用。我们没有发现在评估隐秘果实和显眼果实（成熟和未成熟）时味觉使用上的显著差异。我们的结果表明，非视觉感官在吼猴的果实选择中起着至关重要的作用，根据果实的显眼程度，行为策略存在差异。成熟和未成熟果实的多模态信号使吼猴在食用前能够评估其适口性。
