aphodiine dung beetles
Family: Scarabaeidae Subfamily: Aphodiinae
The subfamily Aphodiinae is diverse in species, but fairly uniform in body shape. The subfamily is characterized by small body size and an elongate, cylindrical body form. Coloration is usually brown to black (Ratcliffe and Paulsen, 2008), though more colorful exceptions are known. In Hawaii and Guam, size range is 1.7–8.5 mm (.07–.33 in). Species known from the islands are dark brownish to black, with the exception of Aphodius fimetarius which has shiny reddish elytra. The antennae are 11-segmented, with 3 segments forming the antennal club.
(Ritcher, 1966): Grub C-shaped, not usually hump-backed, cylindrical, and cream-colored. Maxilla with galea and lacinia close together but distinctly separated. Epipharynx trilobed with tormae united mesally. Antennae with 4 or 5 apparent segments. Legs 4-segmented with well-developed claws. Anal lobes whitish or yellowish, lacking setae.
Worldwide. The Aphodiinae are among the most widespread of all scarab beetles, occurring on all continents except Antarctica. They occur in habitats varying from tropical rainforest to alpine tundra (Elias et al., 2000).
The majority of Aphodiinae are dung feeders and are not associated directly with plants. Most species recycle dung and are beneficial for ranching and farming, thus posing no threat to crops or ornamental plants. However, a few species are known to feed on the roots of grasses, particularly Ataenius spretulus and Aphodius granarius (Shetlar and Niemczyk, 1999). Neither species is known from Hawaii or Guam.
This diverse subfamily shows a wide range of life history traits. Most are dung “dwellers” that breed and feed within dung and do not usually tunnel under or roll fecal matter (Ritcher, 1966). A few species, however, are associated with ant or termite nests, are parasitic on other scarabs, or feed on grass roots (Ritcher, 1966).
Minor. The majority of aphodiine dung beetles are either harmless or beneficial to agriculture and horticulture. Indeed, several species were purposely brought to the islands to aid in control of the horn fly (Haematobia irritans), a biting pest of livestock (Markin and Yoshioka, 1998). A few exceptions, such as Ataenius spretulus and Aphodius granarius, are known to be minor pests of sod and turf (Shetlar and Niemczyk, 1999). Neither of these species is currently known from Hawaii or Guam.
Established. Several species of aphodiines are established in Hawaii (Nishida, 2002). Members of the Aphodiinae are recorded from all the major Hawaiian islands except for Kaho‘olawe (Nishida, 2002). Species identification may be hampered by changes in classification and taxonomy (Gordon and Skelly, 2007).
Established. Specimens examined at the University of Guam indicate that several species of Aphodiinae occur on the island, as do species checklists by Bourquin (2002) and Cartwright and Gordon (1971).
Several species of aphodiines were intentionally released in Hawaii, as biocontrol agents (Markin and Yoshioka, 1998). Other species may have been unintentionally transported to the islands (Nishida, 2002).
Aphodiine dung beetles can be separated from the true dung beetles (Scarabaeinae) by examination of antennae (Aphodiinae with 11 segments versus Scarabaeinae with 8 or 9 segments), small size (Aphodiinae at 1.7–8.5 mm [.07–.33 in] versus Scarabaeinae at 2.0–40.0 mm [0.07–1.57 in), and body shape (Aphodiinae are typically elongate and cylindrical versus Scarabaeinae that vary widely in form from rounded or oval to oblong or rarely cylindrical).
Species level fact sheets for the Aphodiinae will be released pending completion of a review of the Hawaiian and Guamanian fauna. Unfortunately, species level identifications for Hawaiian and Guamanian specimens are usually incorrect, and any non-authoritative identification should be regarded cautiously.
Report your observation of these beneficial species at our iNaturalist project.