Effects of nonprotein amino acids on survival and locomotion ofOsmia bicornis

Abstract

To investigate the effects of two nectar nonprotein amino acids, β-alanine and γ-aminobutyric acid (GABA), on Osmia bicornis survival and locomotion, two groups of caged bees were fed with sugar syrup enriched with β-alanine and GABA, respectively. A further control group was fed with sugar syrup. Five behavioural categories were chosen according to the principle of parsimony and intrinsic unitary consistency from start to end, and recorded by scan sampling: two states (remaining under paper or in tubes) and three events (walking on net, feeding from flower and flying). We also analysed the amino acid content of haemolymph sampled from an additional 45 bees fed the same diets (15 per diet type). Bees fed with β-alanine had a significantly shorter survival time than those fed with the control and GABA diets. The GABA diet induced higher levels of locomotion than β-alanine. The former nonprotein amino acid was only detected in the haemolymph of bees fed GABA. The results suggest that insects consuming nonprotein amino-acid-rich diets absorb and transfer these substances to the haemolymph and that nonprotein amino acids affect survival and locomotion. Ecological consequences are discussed in the framework of plant reproductive biology.

Nectar composition in moth-pollinated Platanthera bifolia and P. chlorantha and its importance for reproductive success

“…They also play an important role in modulating insect behaviour. For example, GABA and β-Ala influence insect nervous system and muscle activity (Nepi 2014;Felicioli et al 2018). In the nectar of some plants (e.g.…”

Diversity of nectar amino acids in the Fritillaria (Liliaceae) genus: ecological and evolutionary implications

“…Furthermore, compounds such as proline are sources of short-term energy bursts and can be important in the first phases of insect flight 14,15 . Others, such as GABA (γ-aminobutyric acid), taurine and β-alanine, appear to influence insect behaviour by limiting excessive states of excitation during stressful conditions 16 , or induce higer level of locomotion 17 . Also nonessential amino acids (NEAAs) may play an important role, incorporated from the adult diet into the eggs of butterflies may improve reproductive success of butterflies under suboptimal larval conditions 11 .…”

Nectar in Plant–Insect Mutualistic Relationships: From Food Reward to Partner Manipulation

“…Those more common in nectar, i.e., γ-aminobutyric acid (GABA) and β-alanine, are important insect nervous system neuromodulators ( Nepi, 2014 and references therein). They may affect insect behavior in several ways: by affecting insect nervous system physiology, regulating nectar intake through phagostimulation and promoting muscle function ( Felicioli et al, 2018 ). Among the NPAAs found in nectar, GABA seems of particular interest since in invertebrates GABA-receptors are located peripherally in muscle tissue and neuromuscular junctions bathed in hemolymph ( Bown et al, 2006 ) and may be sensitive to variations in GABA levels caused by insect feeding on GABA-rich nectar.…”