We have been running a 12 m Rothamsted aerial suction trap in Ithaca since 1989. A second of these was installed at the Hill Bank Field Station of the Programme for Belize early in 2001 (see photo at bottom of page). We have found the 12 m sampler to yield an index of insect availability that seems to reflect accurately the availability of insects to foraging swallows, and we have learned a great deal about the aerial insect fauna over Ithaca.
The following figure shows how data from the sampler may help us understand the phenology of laying in populations of swallows.
The above figure presents a histogram of the initiation dates of all known first clutches (i.e., no replacement clutches included) along with a LOWESS data smoothing of the catch from the Rothamsted sampler for two representative years (one with a compact breeding season, 1989, and one in which laying was protracted, 1992).
We have saved all the insect samples from our 12 m sampling, and we are keen to involve entomologists in the analysis of the fauna both in Ithaca and throughout the hemisphere.
The Rothamsted samplers are clearly only worthwhile if one is willing to make a large investment in insect sampling. We are hoping eventually to have an array of 12m samplers deployed throughout the hemisphere at selected Golondrinas sites.
At sites where budget and logistics dictate, smaller and less expensive suction samplers can be deployed to provide comparative data on the seasonal patterns of insect abundance. We have sampled insects in Ithaca with inexpensive 1meter suction samplers, which can be built for less than $100 apiece. A drawback of this model is that the samples they collect are strongly influenced by local patchiness in the emergence of insects.‹— Back to Data Collection & Protocols