Comparative Studies of Perianal Structures in Myrmecophilous Aphids (Hemiptera, Aphididae)

SIMPLE SUMMARY: Aphids involved in obligatory mutualistic relationship with ants are believed to have short cauda and elongated, vertical anal plate to allow keeping the honeydew droplet until removed by ants. Our study indicated no such correlation of morphology and ant-attendance between facultatively and obligatory myrmecophilous aphids. Review through microstructure of perianal cuticle indicated that the microrelief of cuticle may play a role in keeping excreted honeydew away from aphid body until removed by ant worker. ABSTRACT: There are three types of relationships between aphids and ants: non-myrmecophilous, obligatory and facultatively myrmecophilous. The degree of involvement in this mutualism is believed to be corelated with morphological adaptations of perianal structures. In this manuscript, we analyzed the differences of these structures in obligatorily (18 species) and facultatively (10 species) myrmecophilous aphids. Scanning electron microscopy (SEM) and light stereoscopic microscopy (LSM) techniques were used for these studies. Comparison of structures showed no strict relationship between their morphology and the degree myrmecophily, with certain indication that the microsculpture of perianal cuticle may play role in protection of aphids against honeydew droplet in facultatively myrmecophilous aphids.