Fliers and perchers among Odonata: dichotomy or multidimensional continuum? A provisional reappraisal

Abstract

We revisit the hypothesis, first advanced in 1962, that, with regard to their means of thermoregulation and overt behaviour, two types of Odonata can be recognised: fliers, when active (during reproductive activity, primarily, or foraging) remain on the wing, whereas perchers, when similarly engaged, spend most of the time on a perch from which they make short flights. First, in light of the available data, we restrict the hypothesis to apply primarily to activity at the rendezvous. Next, we review evidence, including direct measurements of body temperature coupled with activity budgets, to test the proposition that the hypothetical classification constitutes a dichotomy rather than a continuum. We conclude: (1) that there is merit in retaining the dichotomous classification into fliers and perchers, together with the thermoregulatory capabilities assigned to each category; (2) that the distinction between fliers and perchers is sufficiently discrete to be a useful predictor of the suite of thermoregulatory strategies and energy demands characteristic of representatives of each category; and (3) that, within each category a continuum exists such that the capacity to heat the body by irradiation (i.e. ectothermically) or by metabolic heat production (endothermy) increases with body size. Some departures from expectation based on the percher/flier dichotomy reflect the increased flight activity that occurs at the rendezvous under conditions of heightened conspecific or interspecific interference. Other apparent anomalies are identified as topics for potentially fruitful research.THE FLIERfPERCHER TEMPLATE Forty-six years ago Corbet (1962) hypothesised that, with regard to their means of thermoregulation and overt behaviour, two types of Odonata can be recognised. Fliers are those that, when active, remain on the wing, whereas perchers, when active, spend most of their time on a perch from which they make short flights (Corbet 1962). At the time this difference was rationalised in terms of the dragonfly's need to avoid overheating the body, although this reasoning was based on little more than the inference that, by flying persistently, fliers would be tending to maintain the body temperature at a high level unless they possessed some 'special' compensating

Behavioral ecology of Heteragrion consors Hagen (Odonata, Megapodagrionidae): a shade-seek Atlantic forest damselfly

“…All these interpretations are based on the general thermoregulatory theory of odonates (May 1991;De Marco et al 2005;Corbet & May 2008). Unfortunately, most of the general construction of this theory came from data from Anisopterous dragonflies as recently reviewed by Corbet & May (2008). Otherwise, our data on general behavior, temporal budget and activity pattern of H. consors provide a support of those arguments for this Zygopteran group.…”

“…The behavior of perching with open wings, which is shared with other Megapodagrionidae, could represent a possibility to an increase in body surface favoring convective heat exchange. All these interpretations are based on the general thermoregulatory theory of odonates (May 1991;De Marco et al 2005;Corbet & May 2008). Unfortunately, most of the general construction of this theory came from data from Anisopterous dragonflies as recently reviewed by Corbet & May (2008).…”

“…Odonate thermoregulation is attained through behavioral and physiological responses that affect the metabolic production of heat and heat exchange with the environment. Corbet (1962; but see also a general re-evaluation of the original work by Corbet & May 2008) classified odonate species into two categories in relation to thermoregulatory behaviors: fliers, expected to be endothermic, can regulate the internal production of heat and use gliding as a heat exchange behavior; and perchers, expected to present different degrees of exothermy, and control body temperature only by body posture adjustments and exposition to solar incidence. Small sized odonates are expected to be thermal conformers that are highly dependent on environment temperature and medium sized to larger exotermic species are usually heliothermic more dependent on solar incidence to attained normal activity (May 1976;De Marco & Resende 2002).…”

“…In general, small to medium-sized odonates seems to be more sensitive to temperature variation, while larger odonates will be more dependent to solar radiation as a result of the relation of heat acquisition and the surface/volume ratio (May 1991;De Marco & Resende 2002;Corbet & May 2008). Odonate thermoregulation is attained through behavioral and physiological responses that affect the metabolic production of heat and heat exchange with the environment.…”

Aquatic insects indicate terrestrial habitat degradation: changes in taxonomical structure and functional diversity of dragonflies in tropical rainforest of East Kalimantan

“…This is mainly because the majority of species from the suborder Zygoptera have very specific life history requirements (Corbet 2006;Sahlén 2006). Generally, Zygoptera can be described as "perchers" sensu Corbet and May (2008). This strategy is advantageous in dense primary forest because "perchers" have better motion ability and can be active at lower temperatures compared to "fliers" (Heinrich and Casey 1978;Corbet 2006).…”