Does toxic defence in Nycticebus spp. relate to ectoparasites? The lethal effects of slow loris venom on arthropods

Abstract

The venom produced by slow lorises (Nycticebus spp.) is toxic both intra- and inter-specifically. In this study we assessed the ecoparasite repellent properties of their venom. We tested venom from two Indonesian slow loris species: Nycticebus javanicus and Nycticebus coucang. Arthropods directly exposed to brachial gland secretions mixed with saliva from both species were immediately impaired or exhibited reduced activity (76%), and often died as a result (61%). We found no significant difference in the result of 60-min trials between N. coucang and N. javanicus [X(2)(1, n = 140) = 2.110, p = 0.3482]. We found evidence that the degree of lethality of the venom varies according to the arthropod taxa to which it is exposed. While most maggots (84%) were initially impaired from the venom after 10 min, maggots died after a 1 h trial 42% of the time. In contrast, at the end of 1 h trial, spiders died 78% of the time. For all arthropods, the average time to death from exposure was less than 25 min (M = 24.40, SD = 22.60). Ectoparasites including ticks, members of the arachnid order, are known to transmit pathogens to hosts and may be an intended target of the toxic secretions. Our results suggest that one function of slow loris venom is to repel parasites that affect their fitness, and that their topical anointing behaviour may be an adaptive response to ectoparasites.

Do chemical cues in the venom of slow lorises repel avian predators?

“…For an avian predator, preying on venomous animals is potentially dangerous. In experimental settings slow lorises venom injected in mice (Alterman 1995) or applied to arachnids (Grow et al 2015) is fatal.…”

“…Slow lorises are venomous, i.e. they can inject a substance comprised of saliva and brachial gland oil, with grooves in the powerful front teeth acting as accelerators pushing the venom upwards, allowing slow lorises to kill rodents, various arthropods, other slow lorises, or humans (Alterman 1995;Madani and Nekaris 2014;Grow et al 2015). that potentially warn off predators (Caro 2013), but they also exhibit a suite of characters, including visual (serpentine locomotion and dorsal striping) and auditory components (snake-like vocalizations), which are postulated to mimic cobras Naja spp.…”

STUDI PAKAN KUKANG JAWA (Nycticebus javanicus Goeffroy, 1812) DI TALUN DESA CIPAGANTI, GARUT, JAWA BARAT

“…Menurut Rode-Margono et al (2015), serangga dan artropoda diperkirakan dapat menjadi sumber utama pembentukan senyawa racun yang ada pada kukang. Racun tersebut pada umumnya digunakan untuk mempertahankan diri dari ancaman dan membersihkan tubuh dari ektoparasit (Grow et al, 2015;Nekaris & Starr, 2015). Kukang betina dapat saja memanfaatkan racun tersebut untuk membersihkan anaknya atau pasangannya sebagai bentuk perilaku sosial.…”

Cabinet of Curiosities: Venom Systems and Their Ecological Function in Mammals, with a Focus on Primates

“…He suggested that the toxic proteins in the BGE must be activated by enzymes in the saliva. Grow et al [ 58 ] showed that BGE and saliva combined was also lethal to arthropods. This two-stage venom is unique in the animal kingdom.…”