Kleptoparasitism in the endemic gecko Phelsuma inexpectata: pollen theft from foraging honeybees on Réunion

Interspecific kleptoparasitism (the stealing of already-procured items from other species) has received little attention in tropical reptiles. We report here the second case of kleptoparasitism in tropical lizards, and the first known case of pollen theft by a vertebrate species. Phelsuma inexpectata, a gekkonid lizard endemic to Réunion, was observed robbing pollen pellets from honeybees (Apis mellifera) foraging on Latania lontaroides flowers. Video-records were used to obtain reliable information on gecko-honeybee interactions occurring on L. lontaroides inflorescences. During the 19 observation periods (total duration 140 min) a total of 78 attempts were recorded, at least 40% were successful. Both males and females displayed kleptoparasitic behaviour. A high level of gecko kleptoparasitism occurred, with an average one-robbery attempt every 2 min. Behaviour of both the kleptoparasitic P. inexpectata and its host A. mellifera are described.

Flower Visitors as Cheats and the Plants’ Responses

This chapter describes some of the kinds of cheating committed by flower visitors and what plants can do to avoid the costs of being cheated. While both plants and visitors have many ways of cheating, the diversity and deviousness of cheating by the plants seem to be substantially greater than the surreptitious stealing and ambushing that goes on in the animals. This is not surprising when considered in terms of the so-called life-dinner principle, and what each participant has at stake. The chapter begins with a discussion of how animals cheat by means of floral theft and thus get rewards without effecting pollination, including nectar theft, pollen theft, and florivory. It then examines three main options for defending plants against theft: physical barriers, chemical deterrents, and bribes. It also explains the overall effects of theft on flowers and concludes with an analysis of floral exploitation by hitchhikers and ambush predators.

Pollination of two species of Vellozia (Velloziaceae) from high-altitude quartzitic grasslands, Brazil

The pollinators and breeding system of two species of Vellozia (Velloziaceae) from high-altitude quartzitic grasslands in SE Brazil were studied. Vellozia leptopetala is shrubby and grows solely on rocky outcrops, V. epidendroides is herbaceous and grows on stony soils. Both bear solitary, hermaphrodite flowers, and have massive, short-lasting annual blooms. We evaluated the level of self-compatibility and need for pollinators of 50 plants of each species and 20-60 flowers per treatment: hand self- and cross-pollination, spontaneous pollination, agamospermy and control. The behavior of floral visitors on flowers and within plants was recorded. Both species are mostly self-incompatible, but produce a small number of seeds by self-fertilization. The pollen-ovule ratio suggests facultative xenogamy. They were visited primarily by bees, of which the most important pollinators were two leaf-cutting bees (Megachile spp.). Vellozia leptopetala was also pollinated by a territorial hummingbird. Low natural seed production compared to cross-pollination seed numbers suggests that pollen limitation is the main cause of low seed set. This was attributed to the combined effect of five mechanisms: selfing prior to anthesis, enhanced geitonogamy as a result of large floral displays, low number of visits per flower for the same reason, pollen theft by many insect species, and, in V. leptopetala, delivery of mixed pollen loads on the stigma as a consequence of hummingbird promiscuity.