July Insect Phenology

by Carl Strang

As detailed in the previous post, first flower dates were ahead of previous years by 1-1.5 weeks in July at Mayslake Forest Preserve. Insects also had been appearing early in previous months, but did this likewise continue?

In a word, yes. The 14 species I could compare between this year and last appeared a median 14 days earlier, continuing the trend (range 36 days earlier to 12 days later). The difference was only 4 days earlier than in 2010, however (15 species, range 46 days earlier to 14 days later). The largest difference was between 2012 and 2009, a median of 16.5 days earlier (14 species, range 4 to 36 days earlier). The respective differences in June were 22, 15.5 and 22 days, so there was some convergence in first appearance dates.

The black-legged meadow katydid was as representative as any species, beginning its singing 9 days earlier than in 2011, 4 days earlier than in 2010, and 18 days earlier than in 2009.

In this year of odd weather I do not know what to expect from the data for August.

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