Nepenthespitchersversusthermogenic flowers: Thermal patterns and their role in prey capture and pollination

Abstract

Prey capture in Nepenthes and pollination in angiosperms are two antithetical events; one designed to trap insects and other arthropods (carnivory) and the other to transfer pollen through pollinators (reproduction). In this study, infrared thermography was extensively used to obtain thermal profiles of Nepenthes pitchers and thermogenic and non-thermogenic flowers in field conditions. Confocal and scanning electron microscopy were used to record peristome cross-sectional features and pitcher morphology. N. khasiana pitchers displayed below ambient temperatures during evening-night-morning hours (5 pm to 8-9-10 am); pitcher spots recorded lowest and highest temperatures as 14.4 (6-7 am) and 45.6°C (2 pm), respectively. The average humidities in the night and day periods were 77.15% and 50.15%, respectively. The prey capturing zones in Nepenthes pitchers (peristome, lid and their intersection) are colder favoring prey capture, whereas in thermogenic flowers, floral portions are hotter, providing the thermal requirements for the pollinator. In thermogenic plants, floral zones assist pollination by offering a thermal reward through enzymatic processes; but Nepenthes traps achieve lower temperature spots by physical (surface microstructures), chemical (nectar) and ecological (rain, humidity) factors. Both are contrasting life and death adaptations in nature.

Bait, not reward: CO2-enrichedNepenthespitchers secrete toxic nectar

“…, (Z)-3-hexen-1-ol (tendril: 14.72%, peristome: 5.02%, nectary: 16.18%, lid: 7.79%), 1-hexanol (tendril: 12.73%) and acetoin (nectary: 6.60%) were also detected in N. khasiana tissues. SEM micrographs of N. khasiana tendril, pitcher peristome, inner side of the lid, nectary and digestive zone were previously reported (Baby et al ., 2017; Sujatha et al, 2023).…”