Buds, Bugs and Bienniality: The Floral Biology of Eschweilera tenuifolia (O. Berg) Miers in a Black-Water Flooded Forest, Central Amazonia

Abstract

Research Highlights: Our study establishes the biennial nature of flowering intensity as a life-time energy-conserving strategy; we show unexpectedly high flower:fruit ratios despite extensive predation of buds and flowers by insect larvae; ‘selective’ bud abortion may be a key annual energy-saving strategy. Background and Objectives: We aim to explain the strongly biennial flowering pattern of Eschweilera tenuifolia, an ecologically key tree species of Amazon blackwater-flooded forest, inundated for up to nine months annually, and with large flowers (6 cm in width). Materials and Methods: We quantified the insect infestation of central Amazonian Eschweilera tenuifolia buds and flowers; we measured nectar production from flower opening onwards, examined flower duration and monitored pollen theft. We tested the role of infestation in bud abortion, nectar production and fruit production initiation. Results: Our study shows extensive predation of buds and flowers by insect larvae, as well as selective abortion of heavily infested buds, and limited loss to pollen thieves which fed largely on infertile fodder pollen. Nectar production peaked in the morning, with no nocturnal nectar production recorded. Sucrose levels were similar to congeneric values (mean 37.4%), and near-constant during production. Flower duration (4–5 days) was longer than reported for other congenerics. Conclusions: Insect infestation of buds can play an important role in regulating flower:fruit ratios, thus setting limits on individual total seed set. Individual Eschweilera tenuifolia appear to invest highly in reproduction every second year. Extended flower duration may be a strategy to enhance pollination success, but increases overall reproductive investment. Abortion of heavily infested buds may minimize allocation of energy to malformed flowers, which have a lower chance of attracting pollinators, thus functioning as a short-term energy-saving strategy. Additionally, biennial flowering in E. tenuifolia is likely to be an energy-conserving response in a highly physiologically-challenging environment. Thus, E. tenuifolia exhibits energy-conservation strategies at two divergent temporal scales.

Beans with bugs: Covert carnivory and infested seed selection by the red‐nosed cuxiú monkey

“…Indeed, accessing such supplements from insect larvae may be particularly efficient, since the generally low levels of sclerotization of larval exoskeletons results in their being more easily digested than those of imagoes (Hopkins & Kramer, 1992; Raubenheimer & Rothman, 2013). Furthermore, since infesting larvae are concentrated within the boundaries of the seed, they also represent a clustered resource whose exploitation is more time/energy efficient than the more spatially dispersed adults (Barnett et al, 2020; McNamara & Houston, 1987). This may be significant since, in some fruits, infesting insects can constitute up to 35% of the total mass (Barnett et al, 2022; Barnett, Ronchi‐Teles, et al, 2017; Barnett, Silla, et al, 2017).…”

“…Many primates, including Chiropotes spp., are also known to eat buds (stem, leaf, and flower) and flowers (Boyle et al, 2012; Di Fiore et al, 2008; Felton et al, 2008; Gregory, 2011; Russo et al, 2005). Given the ubiquity of bud‐borers (Hanover, 1975; Sugiura & Yamazaki, 2009), and the often extensive presence of larval insects in budding and open leaves (Liu et al, 2015), and flowers (e.g., Barnett et al, 2020 for Eschweilera tenuifolia , Lecythidaceae), it is possible that covert carnivory occurs here too. Along with observing insectivory on 18 occasions over a year‐long study of Chiropotes sagulatus , Gregory (2011) observed frequent (101 bouts) consumption of Lecythidaceae flowers, and found that most of the fallen flowers inspected on the ground were infested with a variety of insect larvae.…”

“…(e.g.,Barnett et al, 2020 for Eschweilera tenuifolia, Lecythidaceae), it is possible that covert carnivory occurs here too. Along with observing insectivory on 18 occasions over a year-long study of Chiropotes sagulatus,Gregory (2011) observed frequent (101 bouts) consumption of Lecythidaceae flowers, and found that most of the fallen flowers inspected on the ground were infested with a variety of insect larvae.…”