Natural history of Cassida sphaerula Boheman, 1854 (Coleoptera: Chrysomelidae: Cassidinae: Cassidini) on Arctotheca prostrata (Salisb.) Britten (Asteraceae: Arctotidinae) in South Africa, with a checklist of South African Cassidinae (leaf-mining and tortoise beetles)

Authors

Sally Adam, Mossel Bay, South AfricaFollow
Mariana Campos, CSIRO Health & BiosecurityFollow
Hugh D.C. Heron, Queensburgh, Natal, South AfricaFollow
C. L. Staines, National Museum of Natural History, Smithsonian InstitutionFollow
Rob Westerduijn, Voorburg, The NetherlandsFollow
Caroline Simmrita Chaboo, University of Nebraska-LincolnFollow

ORCID IDs

Mariana Campos https://orcid.org/0000-0003-3685-473X

Charles L. Staines https://orcid.org/0000-002-7411-1024

Caroline Simmrita Chaboo https://orcid.org/0000-0002-6983-8042

Date of this Version

7-29-2022

Citation

Adam S, Campos M, Heron HDC, Staines CL, Westerduijn R, Chaboo CS. 2022. Natural history of Cassida sphaerula Boheman, 1854 (Coleoptera: Chrysomelidae: Cassidinae: Cassidini) on Arctotheca prostrata (Salisb.) Britten (Asteraceae: Arctotidinae) in South Africa, with a checklist of South African Cassidinae (leaf-mining and tortoise beetles). Insecta Mundi 0945: 1–23.

Comments

Published on July 29, 2022 by Center for Systematic Entomology, Inc. P.O. Box 141874 Gainesville, FL 32614-1874 USA http://centerforsystematicentomology.org/

Copyright held by the author(s). This is an open access article distributed under the terms of the Creative Commons, Attribution Non-Commercial License,

Abstract

The tortoise beetle, Cassida sphaerula Boheman, 1854 (Coleoptera: Chrysomelidae: Cassidinae: Cassidini) is endemic to South Africa. Its endemic host, Arctotheca prostrata (Salisb.) Britten (Asteraceae) has been introduced in other countries where it is becoming invasive. Cassida sphaerula could provide a potential biocontrol of Arctotheca weeds as it spends the entire life cycle on this host. An intensive field study, with rearing, photography, and short films of C. sphaerula was conducted in its native habitat to document the life cycle. A checklist of Cassidinae genera in South Africa, along with 19 new host records for Cassidini species in South Africa are presented. Oothecae are simple, with few laminate membranes enclosing fewer than five eggs. There are five larval instars. Larvae and adults feed by making a series of cuts in the ventral cuticle, forming an arc, and they consume the mesophyll as the cuticle is rolled to one side. This creates many ventral craters, thickened on one margin with the rolled cuticle; these ventral craters correspond to ‘windows’ in the dorsal leaf surface where the dorsal cuticle is left intact. This unusual feeding pattern is known in three Cas­sida species, all in South Africa. Like many tortoise beetles, instar I initiates a feces-only shield on its paired caudal processes (= urogomophi); this construction is retained, along with exuviae, by subsequent instars. The shield construction was studied by film and dissections. This revealed that the columnar or pyramidal shield in this species has an exterior of dry or moist feces that obscures the central nested stack of exuviae, each exuviae compressed onto the caudal processes. Pupae may retain the entire larval shield of exuviae and feces or only the 5^th instar exuviae; this behavioral flexibility in pupal shield retention is novel for tortoise beetles. Behaviors of C. sphaerula are discussed in the context of phylogenetic characters that can give evolu­tionary insights into the genus, tribe, and subfamily.