Does Dietary P Affect Feeding and Performance in the Mixed-Feeding Grasshopper (Acrididae)Melanoplus bivitattus?

Abstract

Although consequences of limited dietary protein and carbohydrate to performance are well studied for terrestrial insect herbivores, the importance of phosphorus (P) remains poorly understood. We examined the significance of dietary P to performance in fifth-instar nymphs of the grasshopper Melanoplus bivittatus fed artificial diets. Consumption, digestion, developmental rate, and growth in response to different levels of P nested within standard-Protein and carbohydrate diets were determined. Developmental rate was slowest on high-P diets; protein:carbohydrate concentration and P in diets affected frass production and consumption. Approximate digestibility and conversion of digested food were primarily influenced by the protein:carbohydrate quality of the diet but not P. Mass gain was marginally lower in the low-Protein:high carbohydrate diet used in this study. At the individual level, other than small effects to developmental rate at high concentrations for M. bivittatus, dietary P otherwise seems to have little effect on nymphal performance. To the degree that it is important, effects of dietary P depend on the concentrations of protein and carbohydrate in the diet.

Dietary phosphate affects food selection, post-ingestive P fate, and performance of a polyphagous herbivore

“…However, diets with a P content of 0.1% and below or 1% and above could support maximal growth during 3 day time periods when animals had been fed on the optimal (0.5%) diets for most of their lives, suggesting insects have a considerable capacity to buffer effects of non-optimal P consumption. Long-term consumption of diets with a P content of 1.00% or higher suppressed growth, consistent with the 'intake target' behavior of S. americana and with observations of reduced performance of various aquatic consumers (Boersma and Elser, 2006) and some insect species when provided with diets well above the mean P levels for terrestrial leaves (Harrison et al, 2014;Loaiza et al, 2008;Smith, 1960). Together, these results demonstrate that ecologically relevant variation in plant P content affects the behavior and performance of this grasshopper.…”

“…grew faster on diets enriched in P (Frost and Elser, 2002). However, the development rate of the grasshopper Melanoplus bivittatus was unaffected by dietary %P of artificial diets, except for negative effects at the highest levels (Loaiza et al, 2008). Smith (1960) found similar results for M. bivittatus using fertilized wheat, as did Harrison et al (2014), who found no effects of dietary P intake on most fitness parameters of crickets (Gryllus veletis) except for some negative effects of high dietary P on male chirping rate.…”

“…Loaiza et al (2008) found negative effects of high-P synthetic diets (1.74-2.07%P) on the development rate of M. bivittatus. An earlier study reported decreased survival and growth when M. bivittatus nymphs were fed P-fertilized wheat (1.86%P) (Smith, 1960) and suggested that, perhaps counter-intuitively, P fertilizer could be a way to improve wheat crops and decrease pests.…”

“…On the lower end of the P diets, Smith (1960) reported that the low-P wheat (0.17%P) decreased survival relative to control wheat. Loaiza et al (2008) found no negative effect of low dietary P; however, the lowest level of dietary P tested in their experiment was 0.34%, and these tests were run only for one instar (the fifth). The 0.34%P diet was within the plateau range where dietary P had no effect on performance throughout juvenile development (Fig.…”

Discrimination of grasshopper (Orthoptera: Acrididae) diet and niche overlap using next‐generation sequencing of gut contents

“…Melanoplus bivittatus , described as a forb specialist by Joern (1979) and a generalist by Isely (1944) and Loaiza et al. (2008), also had high niche breadth values and multiple plant families present in the gut, making it a generalist. Chortophaga viridifasciata , described as a generalist by Joern (1979) and Tuberville et al.…”