ODONATOLOGICA Journal of the Societas Internationalis Odonatologica

Contents Volume 33, Issue 3 2004

Abro, A. The female seminal receptacle and accessory glands in Pyrrhosoma nymphula (Sulzer) (Zygoptera: Coenagrionidae) p. 237-244. Sperm, transmitted to the female as individual filamentous cells suspended in a liquid medium, are discharged into a thick-walled pouch, the receptaculum seminis, on the dorsum of the vaginal canal. Spermatozoa soon appear concentrated in a single, smaller, pear-shaped accessory sac, the spematheca, attached to the receptaculum-vagina junction. Particular cells in the wall of the accessory sac secrete a material that is thought to be added to the sperm concentrate. The purpose of the accessory sac is to serve as a store ofsperrnatozoa for use in fertilization. A pair of posterior accessory glands has each an efferent duct that opens into the distal region of the vaginal canal; these ducts are provided with an elaborate muscular apparatus probably serving as a pump: in fresh material, efferently directed peristaltic waves have been observed. The glands are presumed to contribute to the investment of the eggs. The apical domains of the glandular epithelial cells contain intraplasmic assemblages of multiplicating bacteroids. They are likely to be transferred to the ooplasm and thereby transmitted to a new generation.

Cordoba-Aguilar, A.; Siva-Jothy, M. T. Sperm displacement ability in Calopteryx haemorrhoidalis (Vander linden): Male and female roles, male limits in performance, and female neural control (Zygoptera: Calopterygidae) p. 245-252. During copulation, C haemorrhoidalis males displace the sperm of rivals stored by the female. During displacement, sperm stored in 2 spermathecae are ejected by the female as a consequence of male genitalic stimulation: the aedeagus distorts 2 vaginal plates in which mechanoreceptive sensilla are embedded. The sensilla control spermathecal sperm release and a wider aedeagus displaces more sperm. There is variation between female female in their sensillum number which might also affect sperm displacement rate. The role of sensillum number and aedeagal width in sperm displacement variation in copulations whose duration was controlled was investigated. Results indicated that only aedeagal width could predict sperm displacement variation. The neural communication between the vaginal plates and both spermathecae was also examined. Previous observations suggested a "lateral" control of sperm ejection between each vaginal plate and its corresponding spermatheca. This was corroborated by stimulating the mechanoreceptive sensilla of females that underwent different surgical treatments: only those females whose vaginal plate nerves were cut, showed no volumetric decline in sperm in the corresponding spermatheca. Finally, the effect of copula duration (number of aedeagal copulatory movements) on sperm ejection was experimentally examined. In natural conditions, males perform approximately 50 aedeagal movements during copulation. There was no difference in sperm volumes between the pairs of females that were subjected to 50 and 80 aedeagal movements of stimulation using the same aedeagus. These results help to understand the nature of the spermathecal sperm displacement mechanism in this sp.

Hacet, N.; Aktac, N. Considerations on the odonate fauna of Turkish Thrace, with some taxonomic notes p. 253-270. The odon. fauna of Turkish Thrace (52 spp./sspp.) is discussed, based on 40 spp./sspp. gathered during 1997-1999 from 86 localities. Lestes macrostigma (Eversm.), Enallagma cyathigerum (Charp.), Aeshna isosceles antehumeralis (Schmidt), Hemianax ephippiger (Burm.), Onychogomphus f. forcipatus (L.), Cordulegaster i. insignis Schneider, Pantala flavescens (Fabr.) and Sympetrum pedemontanum (Muller) are new to this part of Turkey. Among the taxa discussed in some detail are Calopteryx splendens amasina Bart., Chalcolestes parvidens (Artobol.), Lestes v. virens (Charp.) / L. virens vestalis Ramb., Ischmura elegans ebneri Schmidt / I. e. pontica Schmidt, Gomphus vulgatissimus (L.) / G. schneiderii Sel., Onychogomphus f. forcipatus (L.) / O. f. albotibialis Schmidt, Somatochlora meridionalis Nielsen, Libellula fulva Mull. / L. pontica Sel., and O. c. coerulescens (Fabr.) / O. c. anceps (Schneider). Some identification errors in earlier publications are corrected.

McKee, D.; Harvey, I.; Sherratt, T. N. Behaviour of male coenagrionid damselflies towards conspecific females at the water's edge (Zygoptera: Coenagrionidae) p. 271-278. The behaviour of male Coenagrion puella and Xanthocnemis zealandica towards conspecific andromorph and gynomorph females was studied at breeding ponds in the U.K. and in New Zealand respectively. As expected, male attention directed towards copulation wheels (C. puella) did not depend on whether the wheel contained an andromorph or a gynomorph. Similarly, 6 attention directed towards tandem pairs (C. puella and X. zealandica) did not depend on whether the tandem contained an andromorph or it gynomorph. When individual andromorph and gynomorph females (C. puella and X. zealandica) were released at the water's edge they experienced similar levels of attention from males. By contrast, males (X. zealandica) formed significantly more tandems with gynomorphs tethered at the water's edge than with tethered andromorphs. The observations suggest that males readily identify and intercept conspecific females at the water's edge, particularly when in motion, and that andromorphs and gynomorphs are equally susceptible to male attention. Behaviour of males towards tethered females may be atypical compared to that recorded under more natural conditions.

Novelo-Gutierrez, R.; Gonzalez-Soriano, E. The larva of Dythemis maya Calvert, 1906 and a redescription of the larva of D. sterilis Hagen, 1861 with a key to the larvae of the genus (Anisoptera: Libellulidae) p. 279-289. The last instar larva of D. maya is described and illustrated for the first time, based on reared material from Hidalgo, Morelos and Michoacan States, Mexico. The larva of D. maya is the largest of the genus and is remarkably different from other larvae, mainly by the reduced or wanting dorsal protuberances, and in the short lateral spines on the abdomen. A redescription of the larva of D. sterilis and some notes on other larvae of Dythemis are also provided, and A species are keyed.

Utzeri, C.; Ercoli, C. Disturbance by unpaired males prolongs postcopulatory guarding duration in the damselfly Lestes virens (Charpentier) (Zygoptera: Lestidae) p. 291-301. In L. virens, the tandem post-copulatory guarding varies from some minutes to more than 4 hours and appears correlated to the time of the day and disturbance by unpaired males. Using a multiple regression analysis, with guarding duration as the dependent variable and time of day, temperature and disturbance as the independent variables, it is shown that only disturbance significantly explains the model. An experimental test, in which early-occurring tandem males were not disturbed, while late-occurring ones were disturbed (a reverse situation of what happens in the field), showed that the latter kept their ovipositing females for significantly longer times than the former. The capability of males of varying guarding duration accordingly to the density of solitary males allows them to invest more or less time for guarding, according to the actual risk of losing sperm precedence.

Watanabe, M.; Mimura, Y. Diurnal changes in perching sites and low mobility of adult Mortonagrion hirosei Asahina inhabiting understory of dense reed community (Zygoptera: Coenagrionidae) p. 303-313. Shifts between perching sites, the flying behaviour as well as reproductive behaviour of adults were observed. All marked individuals inhabiting the dense reed community floor were followed from sunrise to sunset. Simultaneous observation was carried out by approximately 20 researchers. Every adult, sexually immature and mature, perched at 20 cm above the water surface within the reed community. For immature adults, about 120 flight activities were performed per day. The accumulated length of the movement was 9 m per day. When matured, the number of flight activities increased two-fold and the total length of the movement was 27 m per day. Although this sp. is a percher, showing little movement, increased flight activity by mature individuals caused encounters between individuals, hovering face-to-face. Few tandem flights were observed and females oviposited alone. The behaviour traits of this sp. at low light intensity are discussed.

Brockhaus, T. Development cycles and morphometric differences in a Platycnemis pennipes (Pallas) larval population (Zygoptera: Platycnemididae). p. 315-325. A larval population was studied (1994-1996) on the Zschopau river, Saxony. Germany. In 325 larvae head widths and wing-sheath lengths were measured, and the abdominal segments that were partly or completely covered by the wing-sheaths were counted. Within the population, there was much size variation throughout the yr. This is interpreted in terms of co-occurrence of the univoltine and semivoltine cohorts. The semivoltine F-0 larvae were larger than the univoltine of the same stage. There are more males than females in the larval population.

Gonzalez-Soriano, E.; Delgado-Hernandez, O.; Harp, G. L. Biological notes on Neoerythromma gladiolatum Williamson & Williamson, 1930 with description of its female (Zygoptera: Coenagrionidae) p. 327-331. The female is described and compared with that of N. cultellatum (Hagen in Selys, 1876). A key to separate the female female of both sp. and notes on the taxonomy, biology and distribution of N. gladiolatum are provided.

Zhu, H. Q. In memory of Hsiu-Fu Chao (Xiufu Zhao) (17 May 1917 - 2 May 2001) p. 355-357.

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