Atya innocous (Herbst, 1792)

Rogers, D. Christopher & Cruz-Rivera, Edwin, 2021, A preliminary survey of the inland aquatic macroinvertebrate biodiversity of St. Thomas, US Virgin Islands, Journal of Natural History 55 (13 - 14), pp. 799-850 : 815

Atya innocous (Herbst, 1792)

We found this atyid shrimp in Flamboyan, Cats and Chickens, and Neltjeberg ghuts, from 50 to +200 metres above sea level. This species was the most common Atya species during August but was absent in November. It occurred at the base, and sometimes the lower face, of waterfalls, usually on large rocks, and often in deep shadow or under rocks during the daytime. It was very sensitive to our approach and could detect us from many metres away from their pools. Upon detecting our approach, they would hide in leaf litter packs or under large stones. This behaviour was probably in response to predators such as the Yellow-Crowned Night Heron, Nyctanassa violacea (Linnaeus, 1758) , which is a crustacean specialist and was commonly observed along the ghuts (see also Gardner et al. 2008). At night this filter feeding shrimp was much bolder, appearing in the open where water flow was strongest. Beatty (1968) and Chase and Hobbs (1969) reported A. innocous from St. Croix and Nemeth et al. (2007) reported it from St. Thomas. Pérez- Reyes et al. (2013) summarise the records for this shrimp in Puerto Rico.