Nidificacion y alimentacion en Liatongus rhinocerulus (Bates) (Coleoptera: Scarabaeidae: Scarabaeinae)

This study brings together the results of several years of simultaneous field and laboratory work with Liatongus rhinocerutus (Bates) (Scarebaeidae: Scarebaeinae: Oniticellini). Attempts have been made to determine the food preferences of the adult and for nesting, as well as the process of nest formation and its structure. Under laboratory conditions, adult beetles eat both decaying fungi, carrion, and cow manure. Also in the field they have been found in these three types of food. However, careful monitoring of food preferences throughout the year, continued for three years in the La Michilía Biosphere Reserve located in the Sierra Madre Occidental (State of Durango, Mexico!) shows that they change throughout the year adjusting to the availability of trophic resources. In the conditions of the Michilia. the adult of him rhinocerulus emerge^n July with the start of the rainy season. During July and August the beetle attacks fleshy fungi in a state of decomposition. The consumption of this food coincides with its abundance in the pine-oak forest where the rhinocerulus is collected in Michilía. After two months of taking advantage of an abundant resource, in September, coinciding with the end of the fungi, the rhinocerulus is mainly found on carrion. the trophic specialization of l. rhinocerulus does not exclude that a few specimens may be found on other types of food between July and October. changes in food preference do not represent such an important variation as might be thought at first approximation. In all foods what the adult of l. rhinocerulus consumes (as most adult Scarabaeinae seem to do) are the pasty juices and fluids, and especially the microorganisms that accompany the process of putrefaction in both fungi, carrion, and decomposing fleshy fruits, such as fresh excrement. It is the type of feeding that Halffter and Matthews (1971) refer to with the term do coprobionte. In contrast, the vast majority of Scarabaeinae larvae (but not all) consume the dried remains of accumulated dung in masses and bolamido (cellulosobionte feed). Despite having maintained a series of terrariums with rhinocerulus in the laboratory, to which fungi and carrion were provided, nesting was only obtained in those that were supplied with cattle manure. This succession of food preferences: fungi-carrion for adults, excrement for nesting, that is, for larvae, is one of the first well-documented observations that explain the capture in fungi, decomposing fruit or carrion of species that are supposed to be only coprophagous (for the variation of food in the Scarabaeinae see Halffter and Matthews 1966; Hanski and Cambefort 1991). Our observations give the successive consumption of different foods an opportunistic ecological value. the nest of him rhinocerulus starts in September. It corresponds to a compound nest, with several nest-masses that form true "sausages" in the secondary galleries (3 to 5). In a gallery there may be one to three nest-masses without any physical separation between them. This corresponds to the most primitive level of compound nest within Scarabaeinae nesting Pattern I, according to the scheme proposed by Halffter and Matthews (1966, see also Halffter 1977, Halffter and Edmonds 1982). This very primitive level is only known from another Oniticellini l. monstrosus (Bates). On . rhinocerulus copulation takes place at the entrance to the main gallery previously excavated, but not yet provisioned. The nest consists of a main vertical gallery excavated below the food source and three to five secondary galleries. The male participates in the provisioning of the nest from the surface, cutting small fragments of dung that he receives (a female with the anterior parts at the entrance of the main gallery. The female accumulates these fragments forming the nest-masses, in the proximal (or upper) part of each nest-mass, the egg is laid inside a smooth cell lined with the female's excrement, after which the formation of the next nest-mass begins in the same gallery. The nest comprises an average of 6 to 7 nest-masses. During larval development, the food accumulated by the mother is consumed from top to bottom. the third stage larva prepares the pupal cocoon in the most distal part of its nest-mass, in such a way that between cocoon and cocoon in the same gallery there is an empty space corresponding to the food consumed by the larva during its development. The text gives the times and their development of the different stages of it. rhinocerulus. after which the formation of the next mass-nest begins in the same gallery. The nest comprises an average of 6 to 7 nest-masses. During larval development, the food accumulated by the mother is consumed from top to bottom. the third stage larva prepares the pupal cocoon in the most distal part of its nest-mass, in such a way that between cocoon and cocoon in the same gallery there is an empty space corresponding to the food consumed by the larva during its development. The text gives the times and their development of the different stages of it. rhinocerulus. after which the formation of the next mass-nest begins in the same gallery. The nest comprises an average of 6 to 7 nest-masses. During larval development, the food accumulated by the mother is consumed from top to bottom. the third stage larva prepares the pupal cocoon in the most distal part of its nest-mass, in such a way that between cocoon and cocoon in the same gallery there is an empty space corresponding to the food consumed by the larva during its development. The text gives the times and their development of the different stages of it. rhinocerulus. the third stage larva prepares the pupal cocoon in the most distal part of its nest-mass, in such a way that between cocoon and cocoon in the same gallery there is an empty space corresponding to the food consumed by the larva during its development. The text gives the times and their development of the different stages of it. rhinocerulus. the third stage larva prepares the pupal cocoon in the most distal part of its nest-mass, in such a way that between cocoon and cocoon in the same gallery there is an empty space corresponding to the food consumed by the larva during its development. The text gives the times and their development of the different stages of it. rhinocerulus.