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)

Journal: Insect Conservation and Diversity
Location: Sierra Chincua and Cerro Pelon, Mexico

Monarch butterflies overwinter in the Sierra Chincua and Cerro Pelon, Mexico, for a period of 154 days. During this time, they cluster on oyamel fir trees, which are on average 1.4 °C warmer than surrounding temperatures at night (protecting from freezing) and 1.2 °C cooler during the day (slowing the loss of fat stores). Older trees (with wider trunks) had more beneficial microclimates.

Monarch Butterfly – Danaus plexippus
Oyamel Fir – Abies religiosa

Brower LP, Williams EH, Slayback DA, Fink LS, Ramirez MI, Zubieta RR, Garcia MIL, Gier P, Lear JA, van Hook T, 2009. “Oyamel fir forest trunks provide thermal advantages for overwintering monarch butterflies in Mexico.” Insect Conservation and Diversity, DOI: 10.1111/j.1752-4598.2009.00052.x
Affiliations: Sweet Briar College, VA; Hamilton College, NY; NASA Goddard Space Flight Center; Universidad Nacional Autonoma de Mexico (UNAM); Huntingdon College, AL; National Cathedral School, Washington, DC.