Pollination biology of four sympatric species of Habenaria (Orchidaceae: Orchidinae) from southern Brazil

Abstract

The pollination process and breeding system of the sympatric Habenaria johannensis, H. macronectar, H. megapotamensis and H. montevidensis was documented for native populations from Rio Grande do Sul, Brazil. All species investigated offer a nectar reward (mean values of total sugars ranging from 18 to 26%) concealed in a spur. Habenaria montevidensis is pollinated by butterflies (Hesperiidae, especially of the genus Urbanus) that carry pollinaria on their eyes; the other three species are pollinated by Sphingidae. Habenaria johannensis is pollinated by the moths Manduca rustica and M. sexta that carry the pollinaria at the base of the proboscis. Habenaria macronectar is pollinated by the moths Eumorpha labrusca and M. cf. lucetius, and these bear pollinaria between the palpi. Habenaria megapotamensis is pollinated by moths of M. cf. lucetius that bear the pollinaria on the proboscis. All species studied are self‐compatible, but pollinator dependent. They also displayed high reproductive success (ranging from 69.48 to 97.40%) and male efficiency factors slightly higher than 1, suggesting that at least one flower was pollinated for each flower acting as pollen donor. At the study sites, the investigated Habenaria spp. are isolated (in terms of pollination) by a set of factors that includes differing floral morphologies, different pollinators and/or different pollinarium placement on the pollinator. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, ••, ••–••.

Diurnal SkipperPelopidas mathias(Lepidoptera: Hesperiidae) PollinatesHabenaria radiata(Orchidaceae)

“…This is in contrast to most of the other Habenaria species, which are reported to be pollinated by nocturnal moths (e.g. Singer and Cocucci 1997;Singer 2001;Peter et al, 2009;Pedron et al, 2012). However, it should be noted that the present observations are somewhat biased toward daytime.…”

“…Singer and Cocucci 1997;Singer 2001;Peter et al, 2009;Pedron et al, 2012), and, to a lesser extent, by tipulid crane flies (Singer 2001) and diurnal Heliconius butterflies (Moreira et al, 1996). Even though there are 11 species of Habenaria in Japan (Yokota 1990), there have been few detailed studies of their reproductive biology, and there is little information regarding their floral visitors (Suetsugu and Tanaka 2014 a, b).…”

“…It should be also noted that the pollinia were attached to the skipper's head because orchids, which are pollinated by Lepidoptera, usually deposit their pollinaria on the smooth surface of compound eyes, the proboscis and distal parts of forelegs, since these are the only sites without scales (e.g. Singer and Cocucci 1997;Singer 2001;Peter et al, 2009;Pedron et al, 2012;Suetsugu and Tanaka 2013;Suetsugu and Hayamizu 2014).…”

“…The greatest diversity within the Habenaria is found in Brazil, eastern Asia, and the central and southern regions of Africa (Batista et al, 2006). Despite the size and diversity of this genus, the pollination biology and breeding systems of very few Habenaria species have been studied in detail (Pedron et al, 2012).…”

Effective pollinia transfer by settling moths’ legs in an orchid Habenaria aitchisonii

“…Previous investigations indicated that Habenaria species were predominantly pollinated by lepidopterans (Singer & Cocucci, ; Singer, ; Singer et al, ; Peter et al, ; Pedron et al, ; Ikeuchi et al, ; Xiong et al, ; Zhang & Gao, ; Tao et al, ), which usually have long proboscises. The pollinia in Habenaria species were observed to be placed on various sites on moths’ or butterflies’ bodies, such as on their eyes, heads, or at the base of their proboscises, depending on the match between the nectar spur and pollinator proboscis length (Singer & Cocucci, ; Singer et al, ; Peter et al, ; Pedron et al, ; Xiong et al, ; Johnson et al, ; Zhang & Gao, ; Tao et al, ). In Habenaria limprichtii Schltr., pollinia were observed attached to sphingids’ eyes but sometimes attaching to settling noctuid moths’ legs (Tao et al, ).…”