ODONATOLOGICA Journal of the Societas Internationalis Odonatologica

Contents Volume 30, Issue 4 2001

Cordoba-Aguilar, A. Sperm displacement ability in the damselfly Calopteryx haemorrhoidalis asturica Ocharan: No effect of male age, territorial status, copulation duration and syn-copulatory behaviour (Zygoptera: Calopterygidae) p. 375-380. During copulation and before sperm transfer, odon. males are able to manipulate rival sperm stored in the female sperm storage organs (usually the bursa copulatrix and spermathecae). males of the territorial C. h. asturica use 2 mechanisms for this. Bursal sperm is removed physically whilst spermathecal sperm is displaced via aedeagal stimulation (through a series of abdominal flexions) of the female sensory system that controls spermathecal sperm ejection. Most bursal sperm is removed but there is individual variation in spermathecal sperm displacement. Previous results have found that this variation is related to aedeagal width. In this paper 4 variables that may also explain variation in spermathecal sperm displacement ability are investigated: male age and status (territorial and nonterritorial), duration of the sperm displacement stage and the number of aedeagal stimulatory flexions. Variation in the ability to displace spermathecal sperm, however, was not related to these variables. This suggests that variation in this ability is reliant only on male genitalic attributes, aedeagal width. These results are briefly discussed in terms of current theory of sexual selection as the process propelling genitalic evolution.

Costa, J. M.; Garrison, R. W. Description of the female of Leptagrion aculeatum Santos, 1965 with keys to the known species (Zygoptera: Coenagrionidae) p. 381-394. The female is described and illustrated, and illustrated keys to the known male male and female female of Leptagrion from Brazil are presented.

Lang, C.; Mueller, H.; Waringer, J. A. Larval habitats and longitudinal distribution patterns of Cordulegaster heros Theischinger and C. bidentata Selys in an Austrian forest stream (Anisoptera: Cordulegastridae) p. 395-409. From May 1997 to April 1998 larvae were recorded at the Weidlingbach, a fourth order tributary of the Danube or Vienna, at 12 sampling stations from source to mouth. From the 14 larval instars reported for the genus, 5 (F to F-4; based on head width) could be identified in both spp.; head widths of female larvae were significantly larger than in male. - Both spp. were most abundant within medium sand sediments with a mean grain size (Q50) of 2.04 mm in C. bidentata and 2.79 mm in C. heros. Mean water depths and nose current speeds measured at larval microhabitats were 4.4 cm and 2.3 cm s-1 (C. bidentata) and 5.6 cm and 2.6 cm s-1 (C. heros). During the winter months larvae chose the water depths slightly deeper than during summer. Throughout the observation period, a high proportion of the larvae (C. bidentata: 70-100%; C. heros: 41-90%) were burrowed in sandy sediments, either totally or displaying the typical ambush posture with only head and anal pyramid visible. In winter, the proportion of burrowing larvae was insignificantly higher than in summer. - C. bidentata larvae were most abundant near the sources, preferring first order stream sections (discharge 0.1-3.21 s-1) with high hardness (up to 34 German degrees) and conductivity (up to 1100 muS cm-1) and a high proportion of fine sediments. Although C. heros larvae were also collected at such first order sites, they reached their highest abundance (larval density up to 7.84 specimens per 10 meter shore length) at second order stream sections (discharge 0.3-6.01 s-1) with lower hardness and conductivity and a higher proportion of coarse sediments.

Naraoka, H. Post-copulatory behaviour in the dragonfly Sympetrum parvulum Bartenef (Anisoptera: Libellulidae) p. 411-422. According to their social status, the males are divided into 2 categories: territory holders (territorial males) and non-territory holders (wandering males). The duration of copulation was longer in wandering (461.5+-347.8 s, n=46) than in territorial pairs (201.3+-149.8 s, n=85). Oviposition modes are 3-fold: viz. (1) single, with non-contact guarding (territorial pairs: 115.1+-75.5 s, n=27; wandering pairs: 133.9+-45.5 s, n=14); - (2) tandem oviposition (territorial pairs: 214.6+-76.6 s, n=5; wandering pairs: 141.0+-76.2 s, n=7); - and (3) tandem oviposition+non-contact guarding (NCGO) (territorial pairs: 131.6+-93.8 s, n=5; wandering pairs: 157.5+-72.8 s, n=2). The first type was most common in territorial (75%) and in wandering pairs (62.1%). The second type was in wandering pairs (24.1%) twice as frequent as in territorial pairs (10.4%). The third mode was infrequent (territorial pairs: 14.6%, wandering pairs: 13.8%). The relationships between male social status and the interference of territorial male male on one hand, and the duration of copulation and the oviposition mode on the other, are discussed. The effects of vegetation and air temperature on the oviposition mode are briefly outlined.

von Ellenrieder, N. The larvae of Patagonian species of the genus Aeshna Fabricius (Anisoptera: Aeshnidae) p. 423-434. The last larval instar of Aeshna absoluta Calvert 1952 and A. confusa Rambur 1842, as well as that of the light form of Aeshna variegata Fabricius, are described for the first time and compared with the other Patagonian larvae of this genus. They can be identified based on prementum width/length ratio, number of teeth on each side of the prementum median cleft, shape of prothoracic processes and relative length of the terminalia.

Andrew, R. J. Evidence of sperm displacement in Ischnura aurora (Brauer) (Zygoptera: Coenagrionidae) p. 435-439. Five spindle-shaped sperm 'pellets' (bundles) were found in the vagina of copulation-interrupted androchrome female. The second and third pellets had a long thin tail while the fourth had partly and the fifth completely disintegrated. In an other female, the vagina was packed with sperm material even though the sperm storage organs (spermatheca and bursa copulatrix) were completely filled. It is proposed that this sp. exhibits a transitional reproductive behaviour with respect to sperm competition.

Gonzalez-Soriano, E.; Novelo-Gutierrez, R. Lestes alfonsoi spec. nov., a new damselfly from Mexico (Zygoptera: Lestidae) p. 441-444. The new sp. is described, illustrated and compared with L. simplex Hag. Holotype male and allotype female: Veracruz, Laguna de Santo Domingo, 4 km NW of Huatusco, alt. 1300 m, 9-VII-2000; deposited at CNIN, UNAM, Mexico.

Martens, A. Perching site choice in Onychogomphus f. forcipatus (L.): An experimental approach (Anisoptera: Gomphidae) p. 445-449. At the rendezvous, males prefer stones as perches. Discrimination experiments with pairs of substrates showed that they land preferentially on perches that correspond in height to the flight level of female female appearing at the water. When they first landed, males preferred perches in the middle of the stream, but afterwards they also used those near the stream margin. The results are interpreted in terms of early recognition of females and rapid formation of tandem linkage.

Mueller, O. ; Suhling, F. Phyllogomphoides litoralis Belle: Description of the final instar larva (Anisoptera: Gomphidae) p. 451-456. Description and illustrations are presented, based on material from the Republic of Panama, reared in the laboratory.

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