Natural history of the social millipede Brachycybe lecontii Wood, 1864

Abstract

The millipede Brachycybe lecontii Wood, 1864 is a fungivorous social millipede known for paternal care of eggs and forming multi-generational aggregations. We investigated the life history, paternal care, chemical defence, feeding and social behaviour of B. lecontii and provided morphological and anatomical descriptions, using light and scanning electron microscopy. Based on observations of B. lecontii from 13 locations throughout its distribution, we report the following natural history aspects. The oviposition period of B. lecontii lasted from mid-April to late June and the incubation period lasted 3–4 weeks. Only males cared for the eggs and subsequent care of juveniles was not observed. In one case, the clutches of two males became combined and they were later cared for by only one of the males. The defensive compound of B. lecontii is stored in large glands occupying a third of the paranotal volume and were observed only in stadia II millipedes and older. We observed B. lecontii feeding on fungi of the order Polyporales and describe a cuticular structure on the tip of the labrum that may relate to fungivory. We found that their stellate-shaped aggregations (pinwheels) do not form in the absence of fungus and suggest the aggregation is associated with feeding. We describe and illustrate a previously undescribed comb-like structure on the tibia and tarsi of the six anterior-most leg-pairs and measure the colour and spectral reflectance of the B. lecontii exoskeleton.

First steps toward suctorial feeding in millipedes: Comparative morphology of the head of the Platydesmida (Diplopoda: Colobognatha)

“…They show various morphological adaptations to different habitats and trophic niches (Golovatch & Kime, 2009; Kime & Golovatch, 2000; Köhler & Alberti, 1990; Manton, 1954, 1961, 1977). Unlike the biting–chewing mouthparts of the large majority of the Diplopoda species, the mouthparts of the predominantly fungivorous Colobognatha (Platydesmida, Polyzoniida, Siphonocryptida, Siphonophorida) are adapted for a scraping–sucking feeding habit (Koch, 2015; Manton, 1961; Verhoeff, 1926–1928; Wong et al, 2020). Within Colobognatha, Platydesmida are a small order with slightly more than 60 described extant species, and a disjunct distribution in North and Central America, Southeast Asia, the European Mediterranean, and the Caucasus (Enghoff et al, 2015).…”

“…99 mya (Moritz & Wesener, 2019; Wesener & Moritz, 2018). The Platydesmida often occur in large aggregations (Lewis, 1984; Shorter et al, 2018; Wong et al, 2020). They are fungivorous (Gardner, 1975; Lewis, 1984; Macias et al, 2019) and assumed to show a suctorial liquid‐feeding mode (Lewis, 1984; Macias et al, 2019; Wong et al, 2020).…”

“…The Platydesmida often occur in large aggregations (Lewis, 1984; Shorter et al, 2018; Wong et al, 2020). They are fungivorous (Gardner, 1975; Lewis, 1984; Macias et al, 2019) and assumed to show a suctorial liquid‐feeding mode (Lewis, 1984; Macias et al, 2019; Wong et al, 2020). Platydesmida are among the few arthropods that exhibit male brood care (Kudo et al, 2009; Wong et al, 2020), which is also a unique behavior within myriapods.…”

“…They are fungivorous (Gardner, 1975; Lewis, 1984; Macias et al, 2019) and assumed to show a suctorial liquid‐feeding mode (Lewis, 1984; Macias et al, 2019; Wong et al, 2020). Platydesmida are among the few arthropods that exhibit male brood care (Kudo et al, 2009; Wong et al, 2020), which is also a unique behavior within myriapods. There are two distinct body types present among the Platydesmida (Enghoff et al, 2015): very slender and elongated, such as in Dolistenus (Figure 1A); and with very wide paranota, such as in Brachycybe , Gosodesmus , and Pseudodesmus (Figure 1B–D).…”

“…The external morphology of the Platydesmida has been described for various taxa (Attems, 1951; Gardner, 1975; Mauriès, 2015; Recuero & Rodríguez‐Flores, 2020; Shorter et al, 2018; Wong et al, 2020). The internal morphology and the muscular system have so far been described for the body rings and legs of Dolistenus savii Fanzago 1876 by Manton (1961, 1977), who also illustrated some muscles of the head.…”