The ecological role of extremely long-proboscid Neotropical butterflies (Lepidoptera: Hesperiidae) in plant-pollinator networks

Abstract

Extremely long proboscides of insect flower visitors have been regarded as an example of a coevolutionary arms race, assuming that these insects act as efficient pollinators for their nectar host plants. However, the effect of proboscis length on generalized or specialized flower use remains unclear and the efficiency of butterfly pollination is ambiguous. Neotropical Hesperiidae feature a surprising variation of proboscis length, which makes them a suitable study system to elucidate the role of extremely long-proboscid insects in plant-pollinator networks. The results of this study show that skippers with longer proboscides visit plant species with deep-tubed flowers to take up food, but do not pollinate them. Skippers equipped with extremely long proboscides seldom include short-tubed flowers in their diet nor visit more plant species than those with shorter proboscides. Our observations indicate that the extremely long-proboscid skippers steal nectar from their preferred nectar host plants, Calathea sp., instead of contributing to their pollination. Finally, we discuss the impact of nectar robbery by these butterflies on their nectar host plants and their legitimate pollinators, euglossine bees.

The specialization continuum in pollination systems: diversity of concepts and implications for ecology, evolution and conservation

“…Borrell ; Johnson & Raguso ; Johnson et al . ; but see Bauder, Warren & Krenn ). Among hummingbirds, in contrast, handling trade‐offs may be large enough to lead to specialization and bill length matching tube lengths of flowers visited (Maglianesi et al .…”

“…Long proboscides in bees and lepidopterans allow such species to obtain nectar from both short-and long-tubed flowers often without large tradeoffs (e.g. Borrell 2005;Johnson & Raguso 2016;Johnson et al 2017; but see Bauder, Warren & Krenn 2015). Among hummingbirds, in contrast, handling trade-offs may be large enough to lead to specialization and bill length matching tube lengths of flowers visited (Maglianesi et al 2014).…”

Anchored phylogenomics illuminates the skipper butterfly tree of life

“…Skippers play a central role in pollination ecology. Recent studies have shown that species with long proboscides feed significantly more often on flowers with long nectar spurs [ 24 ] and are non-pollinating nectar thieves [ 25 ], affecting the pollination success of flowers with purloined nectar. However, in some angiosperm lineages such as orchids, skippers appear to be important pollinators [ 26 ].…”

Morphological fine tuning of the feeding apparatus to proboscis length in Hesperiidae (Lepidoptera)

“…The proboscis of the Neotropical skipper Damas immaculata measured 52.7 mm, equivalent to more than twice the body length and represented the longest proboscis ever recorded in butterflies (Bauder et al, ). These insects with extremely long proboscides showed specialized feeding preferences on flowers with long nectar spurs in Costa Rica (Bauder, Warren, & Krenn, ). Furthermore, the feeding performance of 34 skipper species with varying proboscis lengths from a Costa Rican lowland rainforest area was assessed (Bauder, Morawetz, Warren, & Krenn, ).…”