The article considers the phenomenon of ballistic defaecation by odonate larvae, exhibited by certain Anisoptera but not by any Zygoptera, and explores two possibilities: (1) that ballistic defaecation in Anisoptera may correlate with increased foraging success (the ‘Wudkevich Hypothesis’) by distancing the prey’s alarm pheromone, persisting in the pellet after defaecation, from the larva’s ambush…
Although the endemic damselfly, Platycnemis subdilatata Selys, 1849, is widespread in the Maghreb, many aspects of its reproductive behaviour, biology and ecology are still unstudied. One particular feature of this species is that its coloration pattern continues to change during maturation and afterwards, which makes it a good model for assessing age effects on behavioural…
A hitherto unknown flight pattern of female Calopteryx splendens is described. On a day with heavy winds, when no damselfly could fly in open space of the river, I observed and filmed four to six females foraging in a small bay sheltered by bank vegetation. Females fought for perches and showed a threatening flight with…
It has been shown that life history, behavioural as well as morphological traits vary with the habitats occupied by odonate larvae. Here we ask the following questions: (1) Are the morphological traits, which are associated with perception and foraging, related to the larval habitat? (2) Do these traits influence foraging success and growth rate? We…
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…
In a recent paper D.R. Paulson (2004; IJO 7: 505-515) presented five hypotheses concerning the way wings are held in the Zygoptera during perching. A critical examination suggests that most of them have substantial flaws that prevent their testing. Based on Bechly’s phylogeny (1998;
Sympetrum vicinum is a sit and wait predator, which takes off and pursues small flying insects during its long flying season (July to November). We investigated whether foraging individuals become less discriminating regarding prey size selection during the fall season because the changeable fall weather has an impact on the prey population. To investigate the…
Zygoptera show two perching modes, one with wings closed and one with wings open. These perching modes are distributed unequally through the suborder; most Zygoptera perch with closed wings, but species in 43 genera of eight families at least occasionally – in most cases usually – perch with open wings. Alternative hypotheses to explain this…
Territorial behaviour associated with adult odonate feeding in a Bornean rain forest under-storey is described and its underlying causes are analysed. Immature males and females of all ages of Libellago hyalina defended perches along a narrow trail in kerangas forest, concentrating especially around patches of sunlight. Throughout the day there was displacement of individuals as…