Mixed-species association and a record of a hybrid offspring between Trachypithecus pileatus and Trachypithecus phayrei in Bangladesh

Abstract

The term mixed-species association has a broad range of definitions, from temporary foraging association to permanent group living. A mixed-species association mostly involves species from closely related taxa and is found in birds, mammals and fish. It ranges from passive association with little interaction to coordinated behavioural interactions between the group members of a mixed-species group. Mixed-species association can result in the production of hybrid offspring in the wild. In this study, we present, to the best of our knowledge, the first observational evidence of mixed-species association between the two threatened primate species Phayre’s langur (Trachypithecus pileatus) and capped langur (Trachypithecus phayrei), in fragmented forest patches of northeast Bangladesh. We also report a presumed hybrid offspring between these species. We conducted a short-term study from December 2021 to April 2022 in three forest patches based on information from eco-tourism guides. We confirmed the presence of three mixed-species troops; in two of the groups an adult male T. phayrei had permanently immigrated into a group of T. pileatus, and in the other one an adult male T. pileatus had permanently immigrated into a group of T. phayrei. A long-term detailed study is needed to elucidate the reasons for these mixed-species associations, their behavioural patterns, the fate of the presumed hybrid offspring, and to understand the genetic relatedness between the individuals.

Distribution, social organization, and management of Semnopithecus johnii: An umbrella species of fragmented landscape of the Western Ghats

“…and Trachypithecus spp. in Asia (Al‐Razi et al., 2023; Choudhury, 2008; Lu et al., 2021; Nag, 2020). Such mixed‐species associations are important to understand the possible hybridization leading to the evolution or extinction of lineages (Ackermann et al., 2019; Cortés‐Ortiz et al., 2019).…”

“…in India (Chetan et al., 2014). Mixed species groups are often reported from such overlapping ranges, for example, S. priam and S. johnii (Hohmann, 1988; Nag, 2020; Oates, 1982), S. priam thersites and S. vetulus philbricki (Lu et al., 2021), Trachypithecus pileatus and T. geei (Choudhury, 2008), Nasalis larvatus and T. cristatus (Lhota et al., 2022) and T. pileatus and T. phayrei (Al‐Razi et al., 2023). In some of these cases, hybridization between the mixed species was reported (Lu et al., 2021).…”

First record of a mixed species association between Hatinh langur (Trachypithecus hatinhensis) and red‐shanked douc (Pygathrix nemaeus)

“…Mixed species groups have been well documented in primates, including squirrel monkeys and capuchins in Brazil (Pinheiro et al., 2011 ), Goeldi's monkey and tamarins in Bolivia (Porter, 2001 ), langurs in Sri Lanka and Bangladesh (Al‐Razi et al., 2023 ; Lu et al., 2021 ), Diana and Campbell's monkeys in the Ivory Coast of Africa (Wolters & Zuberbühler, 2003 ), and macaques in China (Burton & Chan, 1996 ). However, none of the Indochina Colobinae primates have been observed to form mixed species group in the wild.…”