Assessment of survey protocol for estimates of abundance for elusive nocturnal primates

Abstract ContextEstimates of a species abundance and habitat preferences provide vital information on their status and the appropriate conservation management. For nocturnal arboreal primates, obtaining reliable estimates of these parameters is particularly challenging because of their cryptic behaviour, often resulting in a small number of detections. Although techniques are available for assessing the abundance of species with a low probability of detection, most require strict assumptions that are difficult to meet. AimsHere, we aimed to explore the possibility of improving nocturnal-primate abundance estimates when detection probability is low and to determine the minimal effort required to calculate reasonable estimates of their overall abundance and the effect of habitat type on abundance estimates. MethodsWe used count data obtained from spotlighting along line transects for estimating density of Bengal slow loris (Nycticebus bengalensis) in north-eastern Thailand with N-mixture hierarchical modelling, to run simulations of varying survey parameters and asses the effort needed to produce robust estimates based on the relative bias from each simulation. Key resultsN-mixture analysis showed that the data obtained from our study were still biased (9%), with a lambda of 1.79 lorises, detection probability of 0.11, 50 survey sites and a maximum of 12 sample occasions. The simulation results found that increasing the number of sample occasions to 14 per transect would produce an acceptable bias (<5%). ConclusionsWe recommend that future studies on nocturnal arboreal species should use preliminary surveys to gauge the specific lambda and probability of detection so as to establish the effort needed to produce reasonable estimates of abundance. ImplicationsOur study showed that count data obtained from spotlighting can be used to produce robust abundance estimates of nocturnal arboreal species. Unlike simple encounter rate, this method incorporates detection probability and habitat preferences, yet does not require additional trained field technicians.

A pinworm's tale: The evolutionary history of Lemuricola (Protenterobius) nycticebi

Lemuricola (Protenterobius) nycticebi is the only pinworm species known to infect strepsirrhine primates outside Africa, and the only pinworm species yet described in slow lorises. Here, we provided a detailed morphological comparison of female and male worms, and a first description of fourth-stage larvae collected from free-living slow lorises (Nycticebus menagensis) in Sabah, Malaysian Borneo. Using mitochondrial and nuclear markers, we also reconstructed the species' phylogenetic relationship with other pinworms infecting primates. Both morphological and molecular results indicated a distinct association between L. (P.) nycticebi and its host. However, while taxonomy identified this species as a member of the Lemuricola clade and grouped pinworms infecting lemurs and slow lorises together, phylogenetic reconstruction split them, placing L. (P.) nycticebi within the Enterobius clade. Our results suggest that L. (P.) nycticebi may represent a different taxon altogether, and that it is more closely related to pinworm species infecting Old World primates outside Madagascar. Pongobius pongoi (Foitová et al., 2008) n. comb. is also proposed.

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Pinworms and their primate hosts have a long history of association.

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L. (P.) nycticebi was recovered from slow lorises in the wild.

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L. (P.) nycticebi was taxonomy classified within the Lemuricola clade.

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However, molecular phylogenetics placed it within the Enterobius clade.

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Taxonomic and molecular identifications should complement species descriptions.