Journal: Ecological Entomology
Location: ?, Canada

The Elm Spanworm hatching boom is 2 weeks after the Sycamore Maple budburst. 85% more eggs were laid on the lower trunk than the crown (although those in later stages of development moved up towards the crown) and it had nothing to do with avoiding parasites (only one pupa was parasitised) or getting better quality leaves, although feeding on older leaves (three leaves expanded per bud) significantly improved the caterpillars’ chance of surviving to adulthood (90%, or 45% higher than when feeding on on younger leaves). Sycamore Maple leaves mature acropetally (from the base up).

Elm Spanworm – Ennomos subsignaria
Sycamore Maple – Acer pseudoplatanus

Fry HRC, Quiring DT, Ryall KL, Dixon PL, 2009. “Influence of intra-tree variation in phenology and oviposition site on the distribution and performance of Ennomos subsignaria on mature sycamore maple.” Ecological Entomology, DOI: 10.1111/j.1365-2311.2009.01091.x
Affiliations: University of New Brunswick, Canadian Forest Service, Agriculture and Agri-Food Canada (AAFC)

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Journal: African Journal of Ecology
Location: Uganda

Blue Gum Chalcids are highly invasive gall-forming wasps that attack eucalypts. In Uganda, there was no infestation found at high altitudes from 1938 to 2452m (the highest tested) above sea level, which includes the range of Maiden’s Gum.

Blue Gum Chalcid – Leptocybe invasa
Maiden’s Gum – Eucalyptus globulus ssp maidenii

Nyeko P, Mutitu EK, Day RK, 2009. “Eucalyptus infestation by Leptocybe invasa in Uganda.” African Journal of Ecology, DOI: 10.1111/j.1365-2028.2008.01004.x
Affiliations: Makerere University, KEFRI (Kenya Forestry Research Institute), CABI (Commonwealth Agricultural Bureaux International)

Journal: Basic and Applied Ecology
Location: Glasshouse experiment, Germany?

When tomatoes were inoculated with the fungal endophyte Acremonium strictum, only 20% of Cotton Bollworm caterpillars survived to adulthood, compared to 54.5% on uninoculated tomatoes, although they still ate the same quantity of leaves.

Tomatoes – Lycopersicum esculentum
Cotton Bollworm – Helicoverpa armigera

Jallow MF, Dugassa-Gobena D, Vidal S, 2004. “Indirect interaction between an unspecialized endophytic fungus and a polyphagous moth.” Basic and Applied Ecology, 5(2): 183-191, DOI: 10.1078/1439-1791-00224
Affiliations: Georg-August-Universität Göttingen

Journal: Science
Location: ?, USA

It is suggested that some pea aphids, a crop pest, are tolerant to heat stress because of bacterial symbionts, Buchnera aphidicola. Members of a strain of heat-sensitive pea aphids with only a non-resistant symbiont were put in 2x2x2m mesh cages, and heat shocks were simulated by putting plastic sheets over the cages (increasing temperature by ~5°C to what would normally affect pea aphid reproduction but still occur naturally). Introduction of predators does not necessarily cause the number of aphids to drop. The number of pea aphids was reduced when subjected to heat shocks, and the presence of 7-spot ladybird predators made no difference (X2 = 2.4, P > 0.5). However, when harlequin ladybirds were introduced, the effect of heat shock was alleviated (X2 = 41.8, P <10–6) because they only predate when population density of aphids is high.

In pairs of one green aphid clone and one red aphid clone, the population growth rate of both red heat-sensitive clones (0.243 ± 0.009) and green heat sensitive clones (0.269 ± 0.008) was greater than their green (0.214 ± 0.007, selection coefficient 0.25) and red (0.247 ± 0.010, selection coefficient 0.20) heat-tolerant counterpart, respectively. When subjected to heat shocks, the growth rate of heat-tolerant clones was notably greater for both green (0.234 ± 0.023 compared to 0.155 ± 0.027 in sensitive reds) and red (0.208 ± 0.031 compared to 0.129 ± 0.033 in sensitive greens) clones. Although the population growth rate was reduced in heat-sensitive clones upon heat shock, this was less than the decrease in growth of heat-sensitive clones (X2A = 12.1, P < 0.001; X2B = 6.96, P < 0.01). Thus rapid evolution of heat-tolerant pea aphid strains may occur if climate change causes more frequent heat shocks.

Pea Aphid – Acyrthosiphon pisum
Seven-Spot Ladybird – Coccinella septempunctata
Harlequin Ladybird – Harmonia axyridis

Harmon JP, Moran NA, Ives AR, 2009. “Species Response to Environmental Change: Impacts of Food Web Interactions and Evolution” Science 323(5919): 1347-1350, DOI: 10.1126/science.1167396
Affiliations: University of Wisconsin, and University of Arizona