Summer Aestivation Research Articles

NATURAL ENEMIES OF PERTHIDA GLYPHOPA COMMON (LEPIDOPTERA: INCURVARIIDAE)

AbstractNatural enemies of immature stages of the jarrah leafminer, Perthida glyphopa are listed. Ten species of Hymenoptera were recorded as parasitoids, achieving 54 and 14% mortality of feeding larvae at low and high leafminer population densities in warm and cool climates, respectively.Large feeding larvae were the most preyed upon (33%) by 9 species of birds at intermediate population densities of the leafminer. At high population density, 3 species of ants collected some 30% of the fallen mature larvae and a further 21% were eaten by earwigs, carabid beetles and ants during summer aestivation.

森戸川（神奈川県三浦半島）におけるホタルトビケラの生活史，特に幼虫の陸上夏眠とよう化および陸上産卵について

The life history of the caddisfly, Nothopsyche ruficollis (ULMER), was studied in a small stream on the Miura Peninsula of Kanagawa Prefecture, Japan, from October 1984 to September 1986. The species had a univoltine life cycle. Adults were present from late autumn to early winter and oviposited their egg-mass on the bank. The hatching time of eggs varied greatly, even within an egg-mass, and newly-hatched larvae remained within the gelation until early spring. They may get into the water with rain. There were five larval instars. Larval development occurred during the aquatic stages of the life cycle, from the first to the early fifth instars, present from early spring to early summer. Final instar larvae began to move on land in the early summer and aestivated from early summer to autumn and pupated in the late autumn. The wintering within the gelatinous egg-mass and summer aestivation observed in this species seems to be advantageous to avoid the unstable stream conditions of drought or flooding prevalence in summer and drought or freeze in winter. Although the main larval food was diatoms, vascular plant and animal materials were also found to be utilized as food by aquatic stages. No feeding was evident in terrestrial larvae.

Assessment of Spring Defoliation to Improve Fall Forage Quality of Bluebunch Wheatgrass (Agropyron spicatum)

Assessment of Spring Defoliation to Improve Fall Forage Quality of Bluebunch Wheatgrass (Agropyron spicatum)

Changes in organic storage compounds during the active and inactive periods in a desert snail, Sphincterochila prophetarum

1. 1. S. prophetarum uses during the aestivation periods of summer and winter only 33% and 22%, respectively, of the total organic storage content, even though the summer aestivation period is much longer. 2. 2. During the long summer aestivation period the snails use a small amount, 0.2% per day, of the different organic storage materials.

Summer survival of the green spruce aphid, Elatobium abietinum, in North East Scotland

In North East Scotland small numbers of all developmental stages of the green spruce aphid survived on Sitka spruce needles during the summer months despite the nutritional inadequacy of these needles for aphid survival following population collapse in early summer. The surviving adults lost weight and fat reserves in response to time and contained low numbers of embryos. No metabolic acclimatization of the respiration rate occurred in response to exposure to different temperatures. Aphid respiration rates during summer were significantly higher than those in winter. Therefore, it was concluded that no summer aestivation occurred. Summer survival was dependent on the ability of a few aphids of all instars to survive on the nutritionally inadequate host, these aphids possibly possessing higher than normal fat reserves or feeding on marginally nutritionally superior trees or shoots.

Aestivation behaviour and thermal relations of the pulmonate Theba pisana in a semi-arid environment

1. 1.|The pulmonate Theba pisana has successfully colonised semi-arid coastal areas in South Africa. Summer aestivation occurs on exposed plant stems. 2. 2.|Upper thermal limits are 49°C for 20 min exposure; 44°C for 3 1 2 h. Climbing avoids these limits. Substrate and air temperatures decline and are less variable above the soil. 3. 3.|Snails select optimum aestivation heights in different vegetation types; settle in the coolest compass sectors; orientate shell mouth upwards and cluster to reduce heating. 4. 4.|Arousal is induced by high temperatures (allowing escape) or by equable combinations of low temperatures and high humidities.

Aestivation and thermoregulation in the texas tortoise, Gopherus Berlandieri

Abstract 1. Deep body temperatures of three Gopherus berlandieri were monitored with radio-telemetry in their natural habitat, in June 1974. 2. In contrast to G. agassizii, this species engages in extensive pre-emergent basking. It does not emerge until its body temperatures have reached minimal voluntary limits. 3. Activity was notably curtailed, indicating summer aestivation. 4. Aestivating tortoises maintained lower average body temperatures than active individuals. 5. Pre-emergent basking allows this species to attain full co-ordination of its functions before exposing itself. This factor allows it to actively escape to shelter when disturbed rather than to depend upon passive resistance.