Temperature and food quality effects on growth, consumption and post-ingestive utilization ef.ciencies of the forest tent caterpillar Malacosoma disstria (Lepidoptera: Lasiocampidae)

Abstract

Temperature and food quality can both influence growth rates, consumption rates, utilization efficiencies and developmental time of herbivorous insects. Gravimetric analyses were conducted during two consecutive years to assess the effects of temperature and food quality on fourth instar larvae of the forest tent caterpillar Malacosoma disstria Hübner. Larvae were reared in the laboratory at three different temperatures (18, 24 and 30 degrees C) and on two types of diet; leaves of sugar maple trees Acer saccharum Marsh. located at the forest edge (sun-exposed leaves) or within the forest interior (shade-exposed leaves). In general, larvae reared at 18 degrees C had lower growth rates and lower consumption rates than larvae reared at the warmer temperatures (24 and 30 degrees C). Moreover, the duration of the instar decreased significantly with increasing temperatures. Type of diet also affected the growth rates and amount of food ingested by larvae but did not affect the duration of the instar. Larvae fed sun-exposed leaves consumed more food and gained higher biomasses. Values of approximate digestibility and efficiency of conversion of ingested food were also higher when larvae were fed sun-exposed leaves. Higher growth rates with increasing temperatures were primarily the result of the shorter stadium duration. The higher growth rates of larvae fed sun-exposed leaves were possibly the result of stimulatory feeding and consequently greater food intake and also a more efficient use of food ingested. This study suggests that the performance of M. disstria caterpillars could be enhanced by warmer temperatures and higher leaf quality.

Biological aspects of Hylesia metapyrrha (Lepidoptera; Saturniidae; Hemileucinae), in laboratory

“…Another factor that has probably interfered with the development of this stage was their non adequacy to the laboratorial conditions for, as it is a species with a very long cycle, its development may be influenced by seasonal climatic variations, as observed from Tolype ventriosa Draudt, 1927 (Lepidoptera; Lasiocampidae) (Specht et al, 2004). With regards to environmental factors, Levesque et al (2002), found evidence of the influence of temperature and luminosity on the larvae development of another lasiocampid, while Daly (1985) showed an influence of the breeding regimens on the growth rates and on morphometry in populations as well as among individuals from the same population.…”

Invasive Spiraea tomentosa: a new host for monophagous Earias clorana?

“…Taking into account the greater toughness of Salix viminalis leaves, the level of mechanical defence of Spiraea tomentosa leaves is obviously not sufficiently effective to defend against E. clorana because this species can also tolerate it. The leaves of Spiraea tomentosa offer larval E. clorana phagostimulants, like sugars (Harborne 1993;Levesque et al 2002), the concentrations of which are greater in Spiraea tomentosa leaves than in those of Salix viminalis. Their higher levels usually result in a shorter duration of larval development and pupal period, as well as greater body mass (Hwang and Lindroth 1997;Kaitaniemi et al 1998;Łukowski et al 2015).…”

Interannual variation in competitive interactions from natural and anthropogenic disturbances in a temperate forest tree species: Implications for ecological interpretation

“…Because larger trees have greater proportions of their canopy exposed to direct sunlight and because light-exposed leaves are the preferred food of FTC (Levesque et al, 2002), larger trees may have suffered proportionally greater defoliation than smaller trees. Hence, larger trees would have been most negatively affected by FTC, whereas the most suppressed trees, for which light availability (GLI) increased by 23-40% without, would have benefited the most from increased light levels from tree removal.…”

“…Species-specific canopy openness parameters determine the degree of light extinction by neighbours but these parameters are estimated from trees with no signs of disease or senescence (Lefranç ois et al, 2008). In reality, both FTC and selection logging would alter light availability for individual trees by introducing intra-specific variation in crown openness from selective feeding behaviour of FTC (Levesque et al, 2002) and, respectively, by intra-and interspecific variation of crown extension growth rates following disturbance (Runkle and Yetter, 1987).…”