Tick Paralysis in Spectacled Flying-Foxes (Pteropus conspicillatus) in North Queensland, Australia: Impact of a Ground-Dwelling Ectoparasite Finding an Arboreal Host

Abstract

When a parasite finds a new wildlife host, impacts can be significant. In the late 1980s populations of Spectacled Flying-foxes (SFF) (Pteropus conspicillatus), a species confined, in Australia, to north Queensland became infected by paralysis tick (Ixodes holocyclus), resulting in mortality. This Pteropus-tick relationship was new to Australia. Curiously, the relationship was confined to several camps on the Atherton Tableland, north Queensland. It was hypothesised that an introduced plant, wild tobacco (Solanum mauritianum), had facilitated this new host-tick interaction. This study quantifies the impact of tick paralysis on SFF and investigates the relationship with climate. Retrospective analysis was carried out on records from the Tolga Bat Hospital for 1998–2010. Juvenile mortality rates were correlated to climate data using vector auto-regression. Mortality rates due to tick paralysis ranged between 11.6 per 10,000 bats in 2003 and 102.5 in 2009; more female than male adult bats were affected. Juvenile mortality rates were negatively correlated with the total rainfall in January to March and July to September of the same year while a positive correlation of these quarterly total rainfalls existed with the total population. All tick affected camps of SFF were located in the 80% core range of S. mauritianum. This initial analysis justifies further exploration of how an exotic plant might alter the relationship between a formerly ground-dwelling parasite and an arboreal host.

Chiroptera

“…Animals present with ascending motor paralysis, with diaphragmatic involvement resulting in labored breathing and eventual respiratory failure. Diagnosis is based on clinical signs and the presence of the tick or an ulcer consistent with prior tick attachment; other gross or histologic lesions are not present (Buettner et al, 2013;Olsson and Woods, 2008). Free-ranging Cynopterus brachyotis infested with teinocoptid mites have acanthosis with dermal fibroplasia subtending the site of attachment of mites (Lavoipierre and Rajamanickam, 1968).…”

Tooth wear, body mass index and management options for edentulous black flying‐foxes (Pteropus alecto Gould) in the Townsville district, north Queensland, Australia

“…The difficulty of determining the age of flying‐foxes means it is also difficult to estimate rates of tooth wear; however, the presence of discolouration and wear on the teeth of many first‐year individuals implies that wear begins early. Flying‐foxes could have long lives, but data for P. conspicillatus and P. poliocephalus suggest that lifespan in the wild is often shortened by shooting, misadventure or, in the case of P. conspicillatus , tick envenomation . The substantial tooth wear observed in our study suggests that estimating age based on tooth wear is an attractive option, but unlikely to be useful.…”

A state-space modelling approach to wildlife monitoring with application to flying-fox abundance

“…The continued decline in the absence of cyclones in the last years of the monitoring points to the possibility that the population may have reached a level where other threats are now keeping it low. These may include one or more of the following; an increase in clearing that occurred in the region during the period 2013–2015 43 , an increasing frequency of extreme temperature events 24 , paralysis tick attack 41 , 44 , persecution in orchards 45 , and the disruption of urban camps 15 . There is currently little evidence to directly link any of these threats to the recent declines, however, unlike cyclones, each of these threats can be managed and should therefore be a focus of management efforts.…”