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Abstract The paper presents a study regarding the aggregations of the Lesser Horseshoe bat Rhinolophus hipposideros in Latium, Central Italy, based on data collected during 27 years in natural caves (limestone) and artificial buildings (abandoned mines, ancient monuments and others). Furthermore some parameters including size, dynamics, sex ratio and age structures are investigated. The number of bats that occur at the hibernacula in winter is low over the whole territory of this region, the most numerous aggregations being 18 individual bats with an average of about 4 bats/visit. In the shelters of the area, the highest numbers of R. hipposideros, a stenotherm thermophilous species, is reached at the end of January, while at the beginning of spring (April) few bats are generally observed. As in many other European populations, males are more commonly represented in winter samples; some caves harbour only adult males over a long time span, about 20 years. The results would suggest that some conservation measures should be introduced to protect this widespread but uncommon and threatened species.

Abstract The present paper summarizes the results of 3 years of observation made at six month intervals for six months at a time (18 field surveys) in a man-made cave in Northern Latium (Central Italy) from April 1992 to April 1995. Its aim is to analyze the main structural and dynamic features of a bat community which hibernates at the shelter. Rhinolophus ferrumequinum and especially Rhinolophus euryale are the most abundant species. Population dynamics of both species as well as that of Rhinoluphus hipposideros show higher levels of abundance between December and February of each semester. In mid-winter, large and sometimes mixed aggregations of Rhinolophus ferrumequinum and Rhinolophus euryale in deep hypothermia occur. A small number of Rhinolophus hipposideros, mainly adult males, was observed. The paper compares the structure of this community to the structure of another community of the same district which has been previously analyzed, in which Vespertilionidae, especially Miniopterus schreibersi, are much more abundant. Despite the difference in species composition, body size was found to be a significant and common feature (as highlighted by forearm length), of the dominant species in both communities, Rhinolophus euryale and Miniopterus schreibersi respectively.

Abstract Sex ratio and structure of Rhinolophus ferrumequinum aggregations of Latium, Central Italy, during hibernation - Sex ratio and demographic structures of nine Rhinolophus ferrumequinum aggregations from as many natural and artificial caves of Latium, Central Italy, were recorded by the Authors. Data were collected from November to April between the years 1976 and 1990. Aggregation sizes are included between 29 and 245 bats. A biased sex ratio in favour of males has been recognized expecially among the greatest aggregations. The abundance of each class (adult and subadult males; adult and subadult females) in every aggregation has been established. Adult females is the rarest class. The strategy of females winter dispersion is analized and discussed according to its adaptive value. Riassunto Sono esposti i risultati di una ricerca sul rapporto sessi e la struttura demografica di nove aggregazioni di Rhinolophus ferrumequinum, censite da novembre ad aprile negli anni compresi tra il 1976 ed il 1990 in altrettante cavità naturali e artificiali del Lazio, Italia Centrale. Le dimensioni delle aggregazioni sono comprese tra 29 e 245 individui. Nelle aggregazioni più numerose, il rapporto sessi è nettamente a favore dei maschi. Di ciascuna categoria (maschi adulti, subadulti, femmine adulte, subadulte) viene analizzata l'abbondanza in ciascuna aggregazione. Le femmine adulte costituiscono il campione più raro. Si discute il vantaggio selettivo della dispersione invernale delle femmine adulte.

Abstract An attempt was made to evaluate the diversity and distribution of cave bats of Latium (Central Italy). Data about twelve species were examined and their frequency have been determined. Only Rhinolophus ferrumequinum and R. hipposideros are really frequent: the other species are more or less localized. The average number of species (2,63) has a great importance for future contro1 of cave bat populations. Similarity between cave bat coenosis was examined, together with the altitude distribution of five species. The relation between altitudinal range, number of caves and average number of species was also studied: between 801 and 1000 m.s.l., the last parameter increases considerably and a hypothesis is presented to explain the phenomenon. This troglophilous bat fauna is probably very rich in species in comparison with other Italian bat communities. Riassunto Viene svolta un'analisi delle cenosi di Chirotteri troglofili dell'Italia Centrale. Vengono esaminati i dati relativi a 12 specie; di ciascuna è stata determinata la frequenza. Rhinolophus ferrumequinum e R. hipposideros risultano le specie più frequenti. I1 numero medio di specie (2,63) assume un importante significato ai fini del controllo delle chirotterofaune troglofile. L'affinità tra le chirotterofaune è stata esaminata, analogamente alla distribuzione altitudinale di cinque specie. Range altitudinale, numero delle cavità e numero medio di specie sono comparati: fra 801 e 1000 m, si osserva un aumento dell'ultimo parametro e vengono formulate ipotesi per spiegare il fenomeno. La ricchezza di specie del Lazio viene evidenziata dal confronto con altre chirotterofaune troglofile regionali italiane.