THE LOCATION OF CONTACT CHEMORECEPTORS SENSITIVE TO SUCROSE SOLUTIONS IN ADULT TRICHOPTERA

¹ Department of Zoology and Entomology, The Pennsylvania State University, University Park, Pennsylvania, and Mt. Desert Island Biological Laboratory, Salisbury Cove, Maine

The loci of contact chemoreceptors sensitive to sucrose and NaCl in solution and mediating feeding responses were determined experimentally in adult Trichoptera of four species from the families, Phryganeidae and Limnephilidae. The receptors are on the ventral surfaces of all the tarsi, the tips of the maxillary and labial palpi and the haustellum. The animals feed on liquids, and these receptors allow them to distinguish acceptable from non-acceptable materials in solution. Less precise observations on two other species from two other families showed a similar situation in these. The end-organs are probably trichoid sensilla. This fact, along with the presence of tarsal contact chemoreceptors, places adult Trichoptera of these species, at least, among typical haustellate insects, most nearly resembling many Diptera in locations of the receptors and feeding reactions.