lower evo-transpiration rate. BREEDING BEHAVIOR Males aggregate in spaced out choruses after sunset into late night in shallow slow-moving pools along the edges of streams. Males located in water, and less often the ones in trees, emit a low-frequency ‘rumbling’ vocalization. Males influence each other's calling behaviors and often neighboring males alternate in their calls. Males in water engage in scramble battles before mating. Reproduction is synchronous in the B. occidentalis species. When females arrive and are fully submerged they are immediately clasped by males. Pairs of males and females are often amplected by several additional males. Males keep their cloaca closely adpressed to the female's cloaca and egg deposition occurs seconds after mating. Eggs immediately attach in a single layer to surrounding submerged stones. Eggs are around 2.2-2.5 mm in diameter and are initially black with a large white pole immediately after oviposition, but gastrulate and become fully black within a few hours. VOCALIZATION Calls of the male Boophis occidentalis are emitted at irregular intervals and are composed of unharmonious notes with no clearly arranged regular series. Notes are composed of 26-34 pulses and each note is 262-362 ms long. The duration of note pulses is 3-5 ms with intervals of 4-8 ms in between. The last pulse of notes is more intense, harmonious, sounds ‘click’ like and is longer than a normal pulse with a duration of 5-18 ms. Pulse repetition rate is 90-109 pulses/second with a frequency of 900–200 Hz. Boophis occidentalis calls are similar to species Boophis albilabriscalls. Major differences between calls are B. albilabris notes are composed of less pulses with each note duration being longer Pulse duration is similar but has longer intervals between pulses. B. albilabris exhibit a different ‘click’ pulse that is more isolated and longer. Pulse repetition is shorter and frequency of notes are higher. References Sources Glaw, F., Vences, M. & Cadle, J. 2004. Boophis occidentalis 2006 IUCN Red List of Threatened Species. Downloaded on 23 July 2007. Andreone, F., Vences, M., Guarino, F.M., Glaw, F. & J.E. Randrianirina (2002): Natural history and larval morphology of Boophis occidentalis (Anura: Mantellidae: Boophinae) provide new insights into the phylogeny and adaptive radiation of endemic Malagasy frogs). – J. Zool., 257: 425–438. Andreone, F., Mercurio, V., Mattioli, F. & Razafindrabe, T.J. (2007) Size at metamorphosis of Boophis occcidentalis Glaw & Vences, 1994 in an arid environment of central-southern Madagascar. Salamandra, 43, 119–121. occidentalis