by Francis Cabana, Research Coordinator
It has been a slow yet exciting start for slow loris research in 2015. LFP member Nabajit Das has published results from his PhD in the Oryx (an important conservation journal). He studies the largest of the slow lorises, the Bengal slow loris (Nycticebus bengalensis).
This species is classified as vulnerable by the IUCN, yet there are few field data to confirm or deny this conservation status within India. Das wanted to investigate the large loris’s actual status and distribution all the while assessing potential threats. After covering 370 km of transects, they only encountered 25 Bengals in 10 sites. Generally low encounter rates in this study were comparable with the rates from other studies on this species in other areas in India, however they were higher in this study. This is possible good news; Bengals are slowly increasing their populations within protected areas.
The author did, however, cleverly note the differences in methods employed with this study versus other which may have led to a higher detection rate. The authors end by stating the observed rates in this study are consistent with the current IUCN red list category.
A very exciting review of chemo-signaling by Drea compares many different primate taxa’s use, and relates them to sex.
According to this review, lorises mainly use chemo-signaling as a means of dispersing scent either on their own bodies or their mate’s bodies. Slow and slender lorises both use urine as a means for chemo-signalling, probably in relation to territorialism and possible mate acquisition. Males which countermark another male’s urine are apparently preferred to the females. There is still much to learn about primate olfactory communication, and our slow lorises are no different!
This is a nice segway into a study that looked at the vomeronasal organ of ring-tailed lemurs, and compared its application and morphology to other primates, including our lorises. Lemurs are known to perform a Flehmen, which is the intake of a scent particle which is then run up and down their hairs and soft palate where the vomernasal organ is located.
It’s like having a mini chemistry lab in the lemur’s face which allows it to get a lot of information from a bit of urine or feces, such as individual, sex, life stage and breeding status. Lorises have never been observed performing this behaviour.
The length of vomeronasal organ in the lemur is allometrically scaled with all related stepsirrhines, including lorises; however, they do secrete significantly more than loris organs.
The last study is by LFP team, aimed at looking at the effects of slow loris venom and their effects on arthropods. We all know by now that slow lorises are venomous. They mix their saliva with oil from their brachial glands which results in slow loris venom. This study shows that the venom is definitely toxic and even lethal to a variety of arthropods.
The venom was more lethal for spiders and ants than for maggots and caterpillars. The authors point out this can have a very important effect in deterring ectoparasites such as ticks. In the field we have never found a healthy adult loris with ecoparasites, again lending credence to the hypotheses that spreading their venom over their fur repels ectoparasites.
Lots more to come this year from the LFP team. We will keep you posted!