Energy dynamics of Encoptolophus sordidus costalis (Scudder) (Orthoptera: Acrididae) in a grassland ecosystem

Abstract

The bioenergetics of annual populations of the dusky grasshopper, Encoptolophus sordidus costalis, on a natural grassland site were examined. Peak dry weight biomass of these insects reached 1.7 kg/ha (1.85 lb/at). Oxygen consumption ranged from 2.76 μl/h for first instar nymphs to 82 μl/h for adults, values that equated with an average consumption of 341 ml oxygen/m2 during the growing season. Energy values (cal/mg) of insect body tissue averaged 5.24 while those for exuviae, faeces, and plant material were 5.38, 4.08, and 4.39, respectively. The grasshoppers ingested 2% of the green shoot primary production, which, at the latitude of the Matador experimental site, was equal to 792 kcal/m2 in 1968–69. An additional 8% was cut and dropped so that a total of 10% of the green vegetation was removed by this insect species. Twenty-five percent of the ingested food was metabolized; the rest was voided as faeces. Respiration accounted for 51% of the metabolized energy. Exuviae made up 6 to 11% of secondary production. Ninety-seven percent of the potential energy of the green vegetation removed by the grasshoppers was returned to the "decomposer compartment" of the ecosystem, with only 3% removed or lost from the system.

Scaling of resting and maximum hopping metabolic rate throughout the life cycle of the locust Locusta migratoria

“…This accords well with the exponents of 0.77 and 0.80 derived in two separate studies on resting American locusts, Schistocerca americana (Greenlee and Harrison, 2004a;Harrison et al, 2005), and the exponent of 0.84 determined for resting Encoptolophus sordidus grasshoppers (Bailey and Riegert, 1973). The maximum oxygen consumption rate of locusts undertaking hopping exercise increased with body mass in a near-isometric relationship, scaling with an exponent of 1.01±0.02 when adults were included in the regression, or 0.97±0.02 when adults were excluded (Fig.2).…”

Energetic parameters of a population of Chlamys varia (Bivalvia: Pectinidae)

“…Laboratory measurements of respiration may lead to underestimates of R because of the intentional use of unfed animals and semi-starvation metabolism. Basal metabolism in larger animals covers only a small part of the total energy expenditure (e. g. Van Hook, 1971;Bailey andRiegert, 1973 Banse, 1978;Humphrys, 1978). According to Widdows (1978), experimental observations relating to the multidimensional character of the natural environment give more precise information on quantitative aspects of respiration in field populations.…”

Aboveground vertebrate and invertebrate herbivore impact on net N mineralization in subalpine grasslands

“…Similarly to the leaf-sucking invertebrates, changes in grasshopper abundance also could have had an effect on soil net N mineralization rates in our study. It is known that these invertebrates only consume 20-30% of the plant biomass removed (Bailey andRiegert 1973, Ingrisch andKo¨hler 1998), while the rest is ''dropped'' to the ground and is directly entering the soil food-web. In addition, Belovsky and Slade (2000) showed that increasing grasshopper densities lead to increases in soil N cycling, and Spalinger et al (2012) found increased grasshopper abundance with increasing FIG.…”