Bachikker

126 nAturAl hiStory noteS

PhoToS By l. a. ColoMa

RULYRANA OREJUELA (Orejuela Glass Frog). PREDATION. Spiders commonly prey on amphibians. Menin et al. (2005. Phyllomedusa 4[1]:39–47) providedan extensive review of spiders
preying on amphibians in the Neotropics. Predators belong to
several species of spiders, especially within the families Ctenidae, Lycosidae, Pisauridae, Sparissidae,and Theraphosidae.
Hayes (1983. Biotropica 15:74–76) reported predation by spiders
Cupiennius sp. (Ctenidae) on two species of glass frogs: Hyalinobatrachium fleischmanni and Espadarana prosoblepon.Herein,
we report predation of Rulyrana orejuela by a spider of the family
Clubionidae. This event was observed in an area at the southern border of Reserva Ecológica Cotacachi Cayapas, Provinciade Imbabura, northwestern Ecuador (0.33101°N, 78.93152°W;
670 m). The general locality includes a mixture of secondary
and primary forests in the Low Montane Evergreen Forest. We
observed a femaleClubiona sp. preying on Rulyrana orejuela on
31 Oct 2009 at 2325 h on the Aguas Verdes stream. At the site,
we observed at least three additional juveniles and two adult R.
orejuela. The genusClubiona was recorded only recently from
Ecuador (Yánez-Muñoz and Cisneros-Heredia 2008. Check List
4[1]:50–54). The predation occurred on a dark night with cloudy
sky and air temperature averaging24°C. The spider (cephalothorax and abdomen length CAL = 14.5 mm) and the R. orejuela
(SVL = 13.9 mm) were located over a leaf of Selaginella sp. at
about 150 cm above the water surface of the stream,near a rock
(1.5 m diam) in midstream. This large rock divided the stream
into two parts and formed a small island with herbaceous vegetation, branches, and trunks. The stream had a depth of 25 cmand a width of 7 m. When first sighted the spider was about 10
cm from a dead juvenile R. orejuela. After about 5 minutes the
spider was seen over the frog with its chelicerae embedded in
the...