Many animals navigate in a structurally complex environment, which requires them to detour around the physical barriers that they encounter. Although many studies in animal cognition suggest that they are able to adeptly avoid obstacles, it is unclear whether a new route is learned to navigate around these barriers and, if so, what sensory information may be used to do so. We investigated detour learning in traveling up a tree in the Australian bull ant, Myrmecia midas, which primarily uses visual landmarks. We first placed a barrier on the ants' upward path. Initially, 46% of foragers were unsuccessful in detouring the obstacle. On subsequent trips, the ants became more successful and established a new route. We observed up to eight successful foraging trips detouring around the barrier. We then tested the same foragers in a series of manipulations, including changing the position of the barrier, making a new gap in the middle of the obstacle, or removing the barrier altogether. The ants mostly showed the same learned motor routine, detouring with a similar path as in the initial trials, suggesting that foragers were not relying on barrier cues and therefore learned a new route around the obstacle. When foragers encountered new olfactory or tactile cues, or the visual environment was blocked; however, their navigation was profoundly disrupted. These results suggest that changing sensory information drastically affects the foragers' navigational performance.

The present article focuses the status of angiosperm flora of Sreenagar upazila under Munshiganj district. The study was done from July 2015 to June 2016. A total of 219 plant species of angiosperms was identified belonging to 165 genera and 70 families. Among them 38 species were monocotyledons and 181 plant species were dicotyledons. Herbs were the largest life forms among the angiosperms and contained about 58% of total plant species occurring in this area. Trees and shrubs occupied 23% and 12% respectively. Climbers were 6% but epiphytes (1%) were very negligible in number in the study area. About 51 medicinal plants were recorded from this study. The following species viz. Lasia spinosa, Calamus tenuis, Tinospora crispa, Passiflora foetida and Calotropis procera were recorded only once and hence considered as rare species in Sreenagar upazila. An invasive poisonous plant Parthenium hysterophorus was also found in Sreenagar. Asiat. Soc. Bangladesh, Sci. 43(2): 161-172, December 2017

Many animals navigate in a structurally complex environment which requires them to detour around physical barriers that they encounter. While many studies in animal cognition suggest that they are able to adeptly avoid obstacles, it is unclear whether a new route is learned to navigate around these barriers and, if so, what sensory information may be used to do so. We investigated detour learning ability in the Australian bull ant, Myrmecia midas, which primarily uses visual landmarks to navigate. We first placed a barrier on the ants’ natural path of their foraging tree. Initially, 46% of foragers were unsuccessful in detouring the obstacle. In subsequent trips, the ants became more successful and established a new route. We observed up to eight successful foraging trips detouring around the barrier. When we subsequently changed the position of the barrier, made a new gap in the middle of the obstacle, or removed the barrier altogether, ants mostly maintained their learned motor routine, detouring with a similar path as before, suggesting that foragers were not relying on barrier cues and therefore learned a new route around the obstacle. In additional trials, when foragers encountered new olfactory or tactile cues, or the visual environment was blocked, their navigation was profoundly disrupted. These results suggest that changing sensory information, even in modalities that foragers do not usually need for navigation, drastically affects the foragers’ ability to successful navigate.Subject CategoryNeuroscience and Cognition