Assessment of seasonal variation of diet composition in rodents using DNA barcoding and Real-Time PCR

Feeding ecology of a lesser-known arboreal giant: Grizzled Giant Squirrel (Ratufa macroura), Southern Western Ghats, India

Animal dietary choices help us understand a species' feeding behaviour and are particularly relevant in conservation management. The aim of this study was to gather knowledge on dietary choices and the foraging behaviour of the Grizzled Giant Squirrel (Ratufa macroura) in Chinnar Wildlife Sanctuary, Southern Western Ghats, Kerala, India. The objectives were in particular to determine the food composition, seasonal fluctuations in food selection and feeding technique. Through an observational sampling method, focal animal sampling, the Grizzled Giant Squirrel in Chinnar Wildlife Sanctuary was found to feed on 30 plant species belonging to 18 families. The most used plant family was Fabaceae, with eight species, followed by Moraceae (four species) and Anacardiaceae (two species). The food species consumed included 22 trees, four climbers, one liana, one paraphyte, one shrub and one succulent species. The squirrel spent the most time feeding on Bauhinia racemosa (19.79%), followed by Tamarindus indica (14.08%) and Nothopegia beddomei (9.89%). The squirrel's diet choice was primarily influenced by the availability of food tree species and food resources rather than the season and nontree species were also found in the diet of Grizzled Giant Squirrel. Although the Grizzled Giant Squirrel exhibits some plasticity in its dietary choices, the available diversity of mature trees and plants as food sources appears to be important for its conservation in the fragmented riparian forest of the Western Ghats in Southern India.

A model for voles interference in cultivated orchards

We consider a dynamical system involving seven populations to model the presence of voles in a cultivated orchard. The plant population is stratified by age (three groups) and by health status (being damaged or not). The last equation models the voles with a modified logistic equation with Allee effect, where the modification takes into account the disturbance provided by the human activity on the orchard. Both an analytical investigation and numerical simulations on a case study are presented. The latter support the observed differences in the literature, in terms of number of voles, between cultivated and uncultivated fields.

DNA-based seed intake quantification for enhanced ecological risk assessment of small mammals

To prevent the non-acceptable effects of agrochemicals on arable fields, Environmental Risk Assessment (ERA) aims to assess and protect against a wide range of risks due to stressors to non-target species. While exposure to stress is a key factor in ERA models, exposure values are difficult to obtain and rely on laboratory studies with often debatable relevance to field situations. To improve intake estimates, data from realistic field-based scenarios are needed. We developed calibration curves relating known seed numbers of up to 20 onion and carrot seeds consumed by wild-caught wood mice (Apodemus sylvaticus) to the seed DNA content in the feces. Based on these inferred quantitative relationships, a field trial was run to determine seed intake in a natural setting using realistic levels of seed spillage. Onion DNA was detected in the fecal samples of the wood mice caught in the field, which resembled a seed intake of up to 1 onion seed. No intake of carrot seeds was detected. This is the first-ever study to quantify seed intake in a realistic field scenario using a DNA-based analysis, showing that accurate seed intake estimates can be obtained. Our approach can help to improve risk assessment models through its minimally-invasive and accurate assessment of seed intake by ERA representative and non-target species, which would otherwise be undetectable with traditional methods. Our novel approach and its results are highly relevant to studies of food intake and diet composition for basic and applied research alike.

Investigation into clinicopathological and pathological findings, prognosis, and aetiology of lorikeet paralysis syndrome in rainbow lorikeets (Trichoglossus haematodus)

Objective

To report the temporal and spatial distribution of rainbow lorikeets presenting with lorikeet paralysis syndrome (LPS) and their clinicopathologic and pathologic findings, exposure to toxins, and response to treatment.

Methods

Records of lorikeets admitted in 2017 and 2018 to facilities in south‐east Queensland (QLD) were reviewed and LPS and non‐LPS cases were mapped and their distribution compared. Plasma biochemistries and complete blood counts were done on 20 representative lorikeets from south‐east QLD and Grafton, New South Wales (NSW). Tissues from 28 lorikeets were examined histologically. Samples were tested for pesticides (n = 19), toxic elements (n = 23), botulism (n = 15) and alcohol (n = 5).

Results

LPS occurred in warmer months. Affected lorikeets were found across south‐east QLD. Hotspots were identified in Brisbane and the Sunshine Coast. Lorikeets had a heterophilic leucocytosis, elevated muscle enzymes, uric acid and sodium and chloride. Specific lesions were not found. Exposure to cadmium was common in LPS and non‐LPS lorikeets. Treated lorikeets had a 60–93% See Table 2 depending on severity of signs.

Clinical significance

The primary differential diagnosis for lorikeets presenting with lower motor neuron signs during spring, summer and autumn in northern NSW and south‐east Queensland should be LPS. With supportive care, prognosis is fair to good.