Anatomy and Histology of the Digestive System ofCephalodesmius ArmigerWestwood (Coleoptera, Scarabaeidae, Scarabaeinae)

Elongated hindguts in desert‐living dung beetles (Scarabaeidae: Scarabaeinae) feeding on dry dung pellets or plant litter

“…M/B values of the examined species are 4.4–6.5, without consistent differences between the two genera. They are in the middle of the range 2.5–8.4 calculated from data in Lopez‐Guerrero (2002) and Umeya (1960) for 19 Scarabaeinae (including 18 fresh‐dung feeders, albeit not from the tribe Scarabaeini where Scarabaeus and Pachysoma belong) and hence typical, as is the midgut morphology. Within Pachysoma , measured pellet feeders have significantly ( P < 0.05) longer midguts (M/B values of 6.3–6.5) than do litter feeders (4.4–5.0).…”

“…1) is a simple tube of approximately the same width as the midgut in dung and pellet feeders, and a little wider in litter feeders. This morphology is characteristic of adult fresh‐dung feeders within the Scarabaeinae (Umeya,1960; Miller,1961; Edmonds,1974; Lopez‐Guerrero,2002), whereas many other larval or adult Scarabaeoidea (e.g., Wiedemann,1930; Umeya,1960,1974; Lopez‐Guerrero,2002; Egert et al,2005, Fonseca et al,2011) have a differentiated hindgut with at least one expansion behind the pylorus. H/B values are 0.7–0.8, 1.0–1.4, and 2.0–2.5 in dung, pellet, and litter feeders, respectively (Table 1), and thus increase with the content of coarse plant fragments in the ingested food.…”

“…The length affects gut arrangement: while hindguts of fresh‐dung and pellet feeders (Fig. 1A and B) are simply U‐shaped, a common pattern in scarabaeine dung feeders (Umeya,1960; Lopez‐Guerrero,2002), those of litter feeders need two extra loops to be accommodated in the abdomen (Fig. 1C and D).…”

“…1C and D). From Umeya (1960) and Lopez‐Guerrero (2002), H/B values of the above‐mentioned 19 adult Scarabaeinae can be estimated. The largest (of Copris incertus ) is 2.3; the others are 0.4–1.7, with 16 of them being below 1.5 (Lopez‐Guerrero's data result in an H/B value of 2.4 for Phanaeus vindex , but Fig.…”

“…With this way of feeding (reviewed by Scholtz,2009), specializations of the gut for digesting refractory plant cell walls would seem unnecessary. Indeed, adult wet‐dung feeders typically have a simple, long and coiled midgut without dilatations or diverticula, and an equally simple, much shorter hindgut (Umeya,1960; Miller,1961; Edmonds,1974; Lopez‐Guerrero,2002).…”