In the present study the temporal changes in the volume of the corpus allatum in three experimental groups of adult males (macropterous, reproductive brachypterous and diapausing brachypterous) of the flightless bug Pyrrhocoris apterus were determined and related to the size of male accessory glands. The results revealed wing morph- and age-dependent differences in the corpus allatum volume in males of this bug. In 4-14 day old males, the volumes of the corpus allatum and accessory glands were largest in long-day reproductive brachypters, intermediate in long-day macropters, and smallest in short-day diapausing brachypters. The smaller corpus allatum in young macropterous males than in same aged reproductive brachypterous males was due to the spontaneous fasting of the former. Later, starting on day 18 after adult emergence, i.e. when macropterous males were feeding normally, there were no significant differences in the volumes of the corpus allatum between long-day brachypterous and macropterous males. On the other hand, the corpus allatum of 18-28 day old diapausing brachypterous males was significantly smaller than that of same aged long-day macropterous and reproductive brachypterous males. The sizes of the corpus allatum and accessory glands were significantly positively correlated in macropterous and diapausing brachypterous males. This is the first report of corpus allatum volume-dependent wing morph-related differences in the rate of accessory gland maturation in males of insects with a non-functional macropterism. The role of differential activity of the corpus allatum in the different life history strategies of males of the two wing morphs in this wing-polymorphic insect is discussed.
The effect of wing length (brachyptery and macroptery) on mating activity was investigated in adult males and females of a flightless wing-polymorphic insect, Pyrrhocoris apterus (L.). Mating activity of the brachypterous and macropterous adult bugs was assessed according to 14 different parameters. The competition tests revealed higher numbers of copulations and greater duration of mating activity in brachypterous than in macropterous males. Brachypterous males are between two to four times more successful in competition for females than their macropterous counterparts, depending on the wing morph and physiological status of the females. Decreased mating success of macropterous males is associated with the smaller size of their accessory glands. Lowered competitive ability for mates is a likely penalty associated with macroptery. Receptivity tests showed the highest tendency to mate in reproductive brachypterous females, lower in macropterous females and the least in diapausing brachypterous females. This is the first report of decreased mating propensity of macropterous morphs in insects with non-functional wing polymorphism. The association of lowered mating success with the higher dispersal activity of the macropterous morph in this bug and a trade-off between the ability to reproduce and to disperse in the flightless wing-polymorphic insects is discussed.
1_n the present study we tested whether long-winged (macropterous) and short-winged (brachypterous) adult females of the firebug Pyrrhocoris apterus (L.) differ in their reproductive capacity and length of life. The following seven physiological markers were measured in these females: lengths of the pre-oviposition period (pre-OP), inter-ovipositon period (inter-OP) and post-oviposition period (post-OP), and the mean number of eggs per batch, total number of eggs, mean total number of egg batches laid and lifespan of the females. The results showed that macropterous and brachypterous females significantly differed in the length of the pre-OP, which was significantly shorter in brachypterous (7.95 ± 1.75 days) than in macropterous females (26.84 ± 9.86 days), but there was no significant difference between the lengths of the inter-OP in brachypterous (4.00–8.79 days) and macropterous (3.00–9.89 days) females. In contrast the length of the post-OP was significantly longer in brachypterous (48.23 ± 30.95 days) than in macropterous females (35.02 ± 17.32 days). Except for the 2nd and 3rd egg batches there was no significant difference between the average numbers of eggs in the other egg batches laid by females of the two wing morphs., 2_Total number of eggs laid by macropterous females during their whole lifespan was not significantly lower (326.47 ± 155.65 eggs) than by brachypterous females (382.82 ± 207.52 eggs), but associated with the lower number of egg batches laid by macropterous (13) than by brachypterous females (19). However, there was no significant difference in the longevity of brachypterous (95.43 ± 41.21 days) and macropterous (93.40 ± 21.18 days) females. The relationship of these results to the reproductive arrest, inactivity of the endocrine gland, corpus allatum, and different levels of adipokinetic hormone in macropterous females is discussed., Radomír Socha., and Obsahuje seznam literatury
The long-winged (macropterous) and short-winged (brachypterous) adult males of Pyrrhocoris apterus (L.) from temperate (Czech Republic) and Mediterranean (Israel) populations were analysed for the sexual activity and the functional activity of their accessory glands. The sexual activity of the males reared either under long-day (18L : 6D) or short-day (12L : 12D) conditions was determined by their capability to mate with 5-day-old reproductive females of the brachypterous morph and to fertilize the eggs. The functional activity of accessory glands was characterized by the presence of a specific immuno-marker. Sexual activity of fasting macropterous males from both temperate and Mediterranean populations was almost as high as that observed in the reproductive brachypterous ones. These findings were also confirmed by an immunotest. Contrary to the temperate macropterous males, the feeding arrest in temperate macropterous females was coupled with a non-diapause inhibition of reproduction in spite of long days. A similar kind of difference was observed also in the Mediterranean macropterous bugs reared under short-day conditions. The results showed the sexual difference in reproductive activity of the macropterous morph in P. apterus.