Activity patterns and movement
All tadpoles were caught in shallow parts of the Yesod HaMa’ala ditch. Metamorphosed individuals were observed either within humid leaf litter in the close vicinity to a perennial water body, directly at the water’s edge or in the water. The majority of the individuals discovered during winter months – especially during the first long-term field trip from November 2013 through March 2014 – were land-dwelling juveniles of snout-vent lengths of ~20–30 mm. Adults were mostly detected in the water from February through September, which may correspond to the breeding period (Fig. 4).
Fig. 4. Number of individuals of Latonia nigriventer captured across months. All individuals below 66 mm were considered juveniles, males and females were distinguished on the basis of their foot webbing and the presence of nuptial pads in males.
In general, the frogs appeared to be mainly nocturnal and could frequently be observed in the water after nightfall. Individuals were found solitarily and were not observed in aggregations.
Upon capture, terrestrial individuals first froze in their movement and then tried to escape forward by either slowly jumping or walking. Walking individuals retracted their eyes. Whenever the density of the soil allowed, they forced their way underground head first with retracted eyes by strongly pushing back all limbs in a walking manner. The increased secretion of viscous skin mucus further facilitated the movement through soil or vegetation. Individuals observed at night in the water were usually submerged with exception of the rostral portion of the head (Fig. 2 N). Upon disturbance, they immediately tried to retreat into the water and escape head first into dense thickets of aquatic plants and roots. They were more easily scared (e.g. by our electric torches) than P. bedriagae or H. savignyi. While being handled, adults of both sexes uttered release calls that were similar to the presumed advertisement calls described below but less regular and less intense.
For the frogs for which displacement was recorded by capture-recapture, the distances moved were < 20 m (N = 10), > 20 m < 100 m (N = 4) and ≤ 100 m (N = 5) (Table 1). Three radio-tracked frogs moved no more than 2 m over periods of 5, 5 and 18 days, respectively.