Apiomerus mutabilis Costa Lima, Seabra & Hathaway, 1951

Gil-Santana, Hélcio R. & Forero, Dimitri, 2010, Taxonomical and biological notes on Neotropical Apiomerini (Hemiptera: Heteroptera: Reduviidae: Harpactorinae), Zootaxa 2331, pp. 57-68 : 62-63

Apiomerus mutabilis Costa Lima, Seabra & Hathaway, 1951

( Figs. 17–21 )

Biological data: TACHINID EGGS: Individuals of A. mutabilis were observed in Nova Friburgo, Rio de Janeiro State, Brazil. One male showed four eggs of Tachinidae (Diptera) attached to its scutellum and dorsal portion of abdomen. After the death of the specimen, a fly pupa appeared in the glass it was preserved, but no adult fly emerged from this pupa.

Sticky substance: Two couples of A. mutabilis were observed under laboratory conditions, where copula also occurred ( Fig. 17 ). The specimens were maintained in similar conditions of temperature and humidity to that of the collection locality, but without access to vegetal material or stick substances. They were regularly fed with Trigona sp. ( Hymenoptera : Apidae : Apinae: Meliponini) ( Fig. 18 ). The females deposited eggs ( Fig. 19 ), which were somewhat scattered and appeared desiccating after two to three weeks ( Fig. 20 ). One female laid her eggs on December/22 and the other on December/29. Most of the eggs were not able to develop, probably because of the lack of resin coating them, being desiccated and somewhat scattered ( Fig. 20 ). Only two nymphs were born on January/23 from the eggs of the last oviposition ( Fig. 21 ). Both nymphs were born covered with a sticky, substance on their bodies, which was much denser on the fore legs ( Fig. 21 ).

Discussion: The Apiomerini are recognized for using sticky substances on the anterior tibiae to hold prey, and by having sticky resins on their bodies ( Jensen-Haarup 1920; Wygodzinsky 1947; Barth 1963; Swadener & Yonke 1973a; Johnson 1983; Adis 1984; Eisner 1988; Schuh & Slater 1995; Bérenger & Pluot-Sigwalt 1997; Gil-Santana et al. 2003; Silva & Gil-Santana 2004; Choe & Rust 2007).

Choe and Rust (2007) noted that females of A. flaviventris without access to plant resins deposited eggs that were scattered and dry. This observation agrees with what we found in A. mutabilis . The few nymphs that hatched were nonetheless covered with a dense sticky substance. Swadener and Yonke (1973a) similarly stated that the sticky substance found in the nymphs of A. crassipes (Fabricius, 1803) reared from females without access to resins should be produced by the nymphs themselves. Barth (1963) provided histological evidence for hypodermic glandular cells in the legs and the abdomen of A. nigrilobus Stål, 1872 , which he believed produce the viscous substance. Silva and Amaral (1973), Swadener and Yonke (1973a), and Amaral Filho et al. (1994) reared successfully all stages of respectively A. nigrilobus , A. crassipes and A. lanipes (Fabricius, 1803) in laboratory conditions with no vegetal resinous available, supporting the view that some sticky substance is produced by the Apiomerus themselves.

Larvae of Tachinidae (Diptera) are obligate endoparasites of insects ( Stireman et al. 2006). Heteroptera , particularly Pentatomidae , Coreidae , Nabidae , and Lygaeidae , are parasitized almost exclusively by the Phasiinae , all of which deposit or inject unembryonated eggs ( Wood 1987; Stireman et al. 2006). In South America species of Coreidae , Largidae , Lygaeidae , Pentatomidae , Pyrrhocoridae , and Scutelleridae have been recorded as hosts of Tachinidae ( Guimarães 1977) .

Few records of Tachinidae parasitizing Reduviidae are known (e.g., Yonke & Medler, 1970; Swadener & Yonke 1973b, 1975), and so far we are aware, no records are available on Tachinidae parasitizing apiomerines. Because no adult fly could be obtained, it was not possible to identify the tachinid species, but it is likely a Phasiinae . Future fieldwork would let identify these parasitic tachinids.

Specimens examined: BRAZIL, Rio de Janeiro, 3 males, 2 females, two nymphs, 67 eggs, Nova Friburgo, 22°17´S 42°29´W, 1049 m, XII-2008, II/ III-2009 [MNRJ].

Figures

FIGURES 17 – 21. Apiomerus mutabilis. 17. pair in copula; 18. female feeding on Trigona sp.; 19 – 20. group of eggs; 19. just after oviposition; 20. same after three weeks; 21. first instar nymphs.