The edible katydid Ruspolia differens is a selective feeder on the inflorescences and leaves of grass species Anu Valtonen 1, * , Geoffrey M. Malinga 1,2 , Petra Junes 1 , Robert Opoke 1 , Vilma J. Lehtovaara 1 , Philip Nyeko 3 & Heikki Roininen 1 1 Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland, 2 Department of Biology, Gulu University, Gulu, Uganda, and 3 Department of Forestry, Biodiversity and Tourism, Makerere University, Kampala, Uganda Accepted: 7 May 2018 Key words: Afrotropics, East Africa, grassland, herbivory, multiple-choice, no-choice, nutritional ecology, Poaceae, swarming, Uganda, Orthoptera, Tettigoniidae, edible bush-cricket Abstract Ruspolia differens (Serville) (Orthoptera: Tettigoniidae, Conocephalinae) (its common names includ- ing ‘African edible bush-cricket’, ‘edible grasshopper’, and ‘nsenene’) is an important source of food for humans in East Africa, but its ecology and biology are poorly understood. We explored the host plants of R. differens with a series of no-choice and multiple-choice laboratory experiments using 18 local common grass and sedge species in Uganda. In no-choice experiments, the degree of acceptance differed significantly among the studied plant species, but in only three species were leaves rejected and in one species were inflorescences rejected. The pattern of acceptance among plant species was different in the local vs. swarming populations. Leaves were generally more accepted by the local pop- ulation, whereas inflorescences were generally more accepted by the swarming population. Both leaves and inflorescences were more readily accepted by males than by females. According to the mul- tiple-choice experiments, R. differens preferred inflorescences over leaves. Our results demonstrate that R. differens is a facultatively oligophagous grass-specialist, which has a clear preference for cer- tain grass or sedge species (especially inflorescences), but it accepts many host plants if the preferred ones are not available. To preserve viable natural populations of R. differens in East Africa in the long term, our results draw special attention to the availability of grasslands where accepted and preferred host plants are available year-round. Introduction Ruspolia differens (Serville) (Orthoptera: Tettigoniidae, Conocephalinae), is one of the most consumed edible insects by humans and an important source of food and nutrition in eastern and southern Africa (Agea et al., 2008; Kinyuru et al., 2010; van Huis et al., 2013) (Figure S1). The common names of this species include ‘African edible bush-cricket’, ‘edible grasshopper’, and ‘nsenene’. In East Africa, R. differens are harvested from natural populations during the two annual periods of swarming (Agea et al., 2008). The swarms are known to be capable of migrating long distances and the locations of their source populations are unknown (Bailey & McCrae, 1978). Consequently, no measures for habitat protection have been introduced so far. Recently, inten- sified commercial harvesting with powerful light-har- vesting stations could pose a risk of overexploitation of natural populations in the long term, while the bycatch could pose a risk to populations of other light-attracted insect species. Small-scale mass-rearing methods accessi- ble to local farmers are currently being developed with the aim of enhancing food security in East Africa. How- ever, the major obstacle to such efforts is poor under- standing of the ecology and biology of R. differens, including the host plant species it accepts and prefers. Such understanding is also essential for management of agricultural land and the protection of natural habitats of R. differens in East Africa. Ruspolia differens is a relatively large-bodied (30– 42 mm long; Matojo & Yarro, 2013) and primarily noc- turnal species (Bailey & McCrae, 1978) that is found in grassland habitats (Swaine, 1964) across the Afrotropics *Correspondence: Anu Valtonen, Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 111, FI-80101 Joensuu, Finland. E-mail: anu.valtonen@uef.fi © 2018 The Netherlands Entomological Society Entomologia Experimentalis et Applicata 1–11, 2018 1 DOI: 10.1111/eea.12707