Short Communication

Chemoecology

, Volume 19, Issue 1, pp 63-66

First online:

Faecal shield chemical defence is not important in larvae of the tortoise beetle Chelymorpha reimoseri (Chrysomelidae: Cassidinae: Stolaini)

  • Alexandra BottcherAffiliated withLaboratório de Ecologia Química, Departamento de Zoologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP)
  • , Jorge Paulo ZolinAffiliated withLaboratório de Ecologia Química, Departamento de Zoologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP)
  • , Flávia Nogueira-de-SáAffiliated withLaboratório de Ecologia Química, Departamento de Zoologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP)Departamento de Ecologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul (UFRG)
  • , José Roberto TrigoAffiliated withLaboratório de Ecologia Química, Departamento de Zoologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP) Email author 

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Abstract

The most frequently investigated defence mechanism among larvae of tortoise beetles is protection by faecal shields, which generally present chemicals that are directly sequestered and/or modified from larval host-plants. In the present work we investigate the tortoise beetle Chelymorpha reimoseri that feeds on the leaves of Ipomoea carnea fistulosa (Convolvulaceae), seeking for the importance of this mechanism to their larvae. We show that 4th instar larvae suffer low predation regardless of the presence of shields in field and laboratory bioassays with ants and chicks. Chloroform extract from larvae without shields provided high protection against predation as shown in bioassays in the field, as well as against chicks, suggesting that C. reimoseri does not rely on the shield for protection. The aqueous extract of the shields did not show activity in such bioassays. The compounds responsible for this protection have yet to be identified, and it remains an open question as to whether they are sequestered from the host plant or de novo biosynthesized. This is the first record of chemical defence in cassidine beetles without the need for faecal shields. These findings indicate that more attention should be paid to chemicals present in the tissues of larvae and/or adults of tortoise beetles; the protective compounds sequestered from host plants or de novo biosynthesized can provide an alternative or complementary strategy against predation in these insects.

Keywords

Camponotus crassus Convolvulaceae Gallus gallus domesticus Ipomoea carnea fistulosa Leaf beetles Predation