Summer and autumnal activity patterns of juvenile and adult Dryomys nitedula were investigated in the wild using infrared motion sensor cameras. The study revealed that the forest dormouse is mainly crepuscular and nocturnal during the summer and autumn. Foraging activity started on average 8 min before sunset in June and shifted towards 26 min after sunset in September. The activity usually ended 40 min before sunrise independently of the season. The investigative activity around the nestboxes had three main periods: one between 20:00 and 22:00, one around midnight between 00:00 and 01:00, and a third one before sunrise between 4:00 and 6:00. Diurnal activity was also recorded but it occurred mainly in autumn and was restricted to the nestbox entrance; animals never switched nestboxes during the day if not disturbed. During the night activity, dormice used to investigate almost all nestboxes within their territory. However they showed preferences for only a few nestboxes which were used more frequently as daytime resting sites.
During the 1997 rut, we tested the hypothesis that there are lekking and territorial stags in a herd of approximately 350 free-ranging sika deer living in 5 km2 area in Northern Austria. During five 2-hour observation sessions observers recorded the callings of the sika deer stags from three high seats and simultaneously recorded the direction from which each male was calling. We recorded 2167 calling bouts consisting of 3655 calls. A calling bout consisted of 1 to 9 calls (mean ± S.D., 1.69 ± 1.09). The distance between calling stags was 85.15 ± 3.10 m (LSMEAN ± S.D.) in the centre of the lek and 121.94 ± 4.33 m at its periphery. Our observations suggested that stags were not associated with fixed territories. Rather, all stags took part in lekking with some ‘satellite’ stags more frequently at the periphery of the moving lek. Our results suggest an existence of a large, transient ‘mega lek’ with up to 23 active male participants. The location of the lek varied considerably over the period of observation, but always was associated with feeding places attractive to hinds.
Caterpillars of the poplar lutestring moth, Tethea or, construct leaf shelters that they defend against intruding conspecifics using a combination of vibratory signals and physical aggression. Staged interactions between a resident caterpillar and introduced conspecific were recorded with a video camera and laser vibrometer. Residents crawl towards the intruder and perform three behaviours: lateral hitting, pushing, and mandible scraping. Vibrations caused by mandible scraping result from the caterpillar repeatedly scraping opened mandibles laterally against the leaf surface in bouts lasting 1.16 ± 0.39 s, with an average of 4 ± 1 scrapes per bout. We propose that these scrapes function in leaf shelter defense against conspecifics for the following reasons: Mandible scrapes are produced only by residents; they are generated when a resident is approached by an intruder; the rate of scraping increases as the intruder approaches the shelter; and residents in all trials retain their shelters, with the intruder leaving the leaf within 127.9 ±104.3s from the beginning of the trial. The function and evolutionary origins of vibration-mediated territoriality in caterpillars are discussed. and Jaclyn L. Scott, Jayne E. Yack.