Life history and larval morphology of Monacon (Hymenoptera: Perilampidae), parasitoids of ambrosia beetles (Coleoptera: Platypodidae)

Abstract

Species of Monacon are distributed from Africa to New Guinea and parasitize ambrosia beetles of economic significance to tropical forestry. This study, based on fieldwork in Papua New Guinea and in Seram, Indonesia, provides the first detailed examination of the interaction between these parasitoids and their hosts; Monacon robertsi is a solitary, monophagous ectoparasitoid of the pupa of Crossotarsus barbatus. The phenology of the parasitoid and its host are summarized with life-history diagrams, and information is presented on oviposition, distribution of parasitoids within the gallery system constructed by the host, behaviour of adults both within and outside the gallery system, and sex ratios. A sex pheromone produced by male C. barbatus during the initiation of a gallery system both reinforces host specificity and synchronizes oviposition by Monacon roberstsi with mating of the host. This results in the parasitoid attacking only the first few of many host egg batches, which reduces the overall parasitism rate. Monacon roberstsi eggs are strongly sculptured, suggesting plastron respiration, and are laid on the bark in the vicinity of the entrance to ambrosia beetle galleries. Development is hypermetamorphic; the first instar is a heavily sclerotized planidium that locates and attaches to the host, and subsequent larval instars are grublike and hymenopteriform. The planidia experience high mortality rates while transferring to successive host instars and only a single planidium remains when metamorphosis and feeding begin, which coincides with host pupation. The immature stages of M. robertsi are described and illustrated using both light and scanning electron microscopy and are compared with those of other genera of Perilampidae and with Eucharitidae. The potential of Monacon species as agents of biological control of economically important species of ambrosia beetles is discussed and judged to be poor.

The life history of Pseudometagea schwarzii, with a discussion of the evolution of endoparasitism and koinobiosis in Eucharitidae and Perilampidae (Chalcidoidea)

“…Literature records for internal or external parasitism by planidia on their larval host are known for 27 species of Perilampidae (Chrysolampinae and Perilampinae) and Eucharitidae (Wheeler 1907, Smith 1912, Brues 1919, Ford 1922, Clausen 1923, 1928, 1940a, Wheeler and Wheeler 1937, Clancy 1946, Ayre 1962, Tripp 1962, Askew 1980, Laing and Heraty 1981, Heraty and Darling 1984, Darling and Miller 1991, Darling 1992, 1999, Heraty et al 1993, Heraty 1994, 2000, 2002, Darling and Roberts 1999, Pérez-Lachaud et al 2006, Carey et al 2012, Lachaud and Pérez-Lachaud 2012, Torréns 2013) (cf. Table 1).…”

“…Endoparasitism by the planidia on the host larva is so far known only in some Perilampus (Perilampinae) and all known Gollumiellinae, Oraseminae and Pseudometagea (Eucharitinae). Because the endoparasitic planidia of Perilampidae do not feed, Darling and Roberts (1999) considered the term endoparasitoid inappropriate. However, at least in Eucharitidae, while in or on their larval host, planidia may exhibit sustenance feeding, at most becoming turgid, or may undergo what can be termed growth feeding in which the planida expand to several hundred times their original size (Wheeler 1907, Smith 1912, Tripp 1962).…”

Phylogeny and behaviour of the Gollumiellinae, a new subfamily of the ant‐parasitic Eucharitidae (Hymenoptera: Chalcidoidea)

“…17), which are features shared with Oraseminae and not Eucharitinae (Heraty, 1994, 2000). These nodules are absent in Aperilampinae and Perilampinae (Smith, 1912; Darling, 1992, 1999; Darling & Roberts, 1999), and probably absent in Chrysolampinae, as based on the third‐instar larva (Darling & Miller, 1991).…”

“…Some Perilampus have a planidium that is endoparasitic on the host larva, followed by external development of the planidium and later instars on the primary host pupa (Smith, 1912; Tripp, 1962). In Chrysolampus (Chrysolampinae), Steffanolampus , Monacon , some Perilampus (Perilampinae), and Aperilampus (Philomidinae), the planidum and later instars are always ectoparasitic (Clausen, 1940; Darling & Miller, 1991; Darling, 1992, 1999; Darling & Roberts, 1999). A planidium is unknown in other Chalcidoidea, and is considered as a synapomorphy of Perilampidae + Eucharitidae (Heraty & Darling, 1984; Table 2).…”

As formigas poneromorfas do Brasil

“…As fases posteriores da larva, no entanto, podem ser secundariamente endoparasitas ou hiperparasitas (DARLING; ROBERTS, 1999;. Várias espécies da subfamília Perilampinae são hiperparasitoides, desenvolvendo-se em Tachinidae (Diptera) e Ichneumonidae (Hymenoptera) (CLAUSEN, 1940).…”