Germ cell cluster formation and ovariole structure in Puto albicans and Crypticerya morrilli (Hemiptera: Coccinea). Phylogenetic implications

Abstract

The organization and development of ovaries in representatives of two families (Putoidae and Monophlebidae) of scale insects are described. Developing ovaries of Puto albicans McKenzie, 1967 and Crypticerya morrilli (Cockerell, 1914) consist of numerous clusters of cystocytes that are arranged in the form of rosettes. At the end of the last nymphal instar these clusters start to protrude from the interior of the ovary into the body cavity and the ovarioles begin to be formed. The ovary of a young female is composed of about 200 spherical telotrophic ovarioles devoid of terminal filaments. The ovarioles of C. morrilli contain 8 germ cells (7 trophocytes and a single oocyte). From 25 to 45 germ cells (23-43 trophocytes and 2 or 3 oocytes) occur in the ovarioles of P. albicans. An ovariole of an adult female is subdivided into a trophic chamber (tropharium), vitellarium and ovariolar stalk (pedicel). At each stage of development, the ovaries are accompanied by large cells (termed bacteriocytes) that contain endosymbiotic microorganisms. The organization of the ovary in P. albicans is more similar to that in archaeococcoid scale insects than in neococcoid taxa. In contrast, the number of germ cells per ovariole in C. morrilli is not typical of other archaeococcoids, but resembles the derived condition seen in other iceryine taxa. The classification and phylogeny of scale insects are discussed in the light of these results.

Keywords

• coccinea
• putoidae
• monophlebidae
• puto albicans
• crypticerya morrilli
• scale insects
• ovaries
• clusters of germ cells
• telotrophic ovariole
• oogenesis
• endosymbiotic microorganisms
• phylogeny