Females Of Pyrrhocoris Apterus Research Articles

Brain norepinephrine identified by mass spectrometry is associated with reproductive status of females of the linden bug Pyrrhocoris apterus

Several biogenic amines, including controversial presence of norepinephrine (NE), were identified by the high performance liquid chromatography equipped with electrospray ionisation mass spectrometry in brain complexes of adult females of Pyrrhocoris apterus. Quantitative analysis was performed by the high performance liquid chromatography coupled to electrochemical detector. Levels of NE, dopamine (DA), octopamine (OA) and 5-hydroxytryptamine (5-HT) in brain complexes were measured in reproductive vs. diapause females. In field collected samples, levels of NE and DA were significantly higher in reproductive (May) than in non-reproductive (Sep, Oct, Feb) females. In laboratory females, NE is higher in long day photoperiod (reproduction) than in short day photoperiod (diapause) already from the first week of the adult age, while DA shows differences between the two contrasting photoperiods only from the second week of the adult age. No association between reproductive status and levels of OA and 5-HT was found.

Dynamism in physiology and gene transcription during reproductive diapause in a heteropteran bug, Pyrrhocoris apterus

Reproductive diapause was characterized in females of Pyrrhocoris apterus using physiological parameters (diapause intensity, photoperiodic responsiveness, oxygen consumption, mass and hydration) and changes in relative abundance of mRNA transcripts of eight different genes coding for proteins implemented in energy metabolism, cryoprotectant biosynthesis, biological clocks, and hormonal receptors. Changes in diapause intensity served as a basis for distinguishing successive phases of diapause development, which were driven both endogenously (under constant environmental conditions) and exogenously (in response to a change in environmental conditions). Changes in the relative levels of transcripts of genes coding for aldose reductase ( AR) and sorbitol dehydrogenase ( SoDH) closely matched those of diapause intensity and thus appeared as promising molecular markers of diapause and its development. During the initiation phase, the intensity of diapause and the levels of AR and SoDH transcripts increased and reached a maximum. During maintenance, under a constant temperature of 20 °C and short-day photoperiod, the intensity of diapause and the levels of both transcripts first decreased and, later, were maintained constant. Termination of diapause was stimulated by cold, during which the intensity of diapause and the levels of both transcripts further decreased. Upon resumption of direct development (oogenesis, mating and oviposition), the relative abundances of AR and SoDH transcripts decreased to trace levels.

Mating behaviour and wing morph-related differences in the sexual activity of a flightless bug, Pyrrhocoris apterus (L.) (Heteroptera)

The sexual activity of long-winged (macropterous) and short-winged (brachypterous) adult males and females of Pyrrhocoris apterus (L.) from a temperate opulation (Czech Republic) were compared. The long-term arena tests revealed postponed sexual maturation and lower sexual activity (longer precopulatory period, longer inter-copulatory period, lower copulation frequency and shorter total duration of copulations) of macropterous pairs when compared with brachypterous pairs of the same age. The total sexual activity of both macropterous and brachypterous pairs increased with the age of the adults, but was significantly lower in the macropterous pairs. The short-term tests showed that the lowered mating propensity of macropterous pairs was mainly due to a decrease in the sexual receptivity of the females. It is the first demonstration of wing morph-related differences in the mating activity of P. apterus females and a first report of a mating disadvantage in the macropterous morph of a wingpolymorphic insect whose macropterous specimens have evolved flightlessness. Evolutionary transformation of the “oogenesis-flight” syndrome, that occurs in flying insects, into an “oogenesis-walking” syndrome in the flightless macropters of P. apterus is discussed.

Feeding, drinking and digestive enzyme activities in long‐ and short‐day females of Pyrrhocoris apterus (Heteroptera)

Abstract. .Reproducing females of the firebug, Pyrrhocoris apterus (Linnaeus) (Heteroptera: Pyrrhocoridae), reared under long‐day (LD 18:6h) photocycle (long‐day females), and diapausing females reared under short‐day (LD 12:12h) conditions (short‐day females) were analysed for temporal patterns of feeding, drinking and gut digestive enzyme activities. In long‐day females the highest activities of feeding and drinking were found at the beginning of each reproductive cycle. Significant correlation between feeding and drinking activities in both reproducing long‐day females and short‐day females during pre‐diapause state was found. In pre‐diapausing short‐day females the cyclical pattern of feeding and drinking was maintained despite the inhibition of reproduction. After entering the diapause their feeding activity became very low. Analysis of five gut enzymes revealed that short‐day females differ significantly from long‐day females in higher protease, amylase and esterase activities, in case of lipase only at certain times of their adult life; no significant difference was found in the aminopeptidase activity. Positive correlations between intensity of feeding and gut enzyme activities were observed in short‐day females. Using several protease inhibitors most protease activity in the gut of P.apterus was identified as cysteine and aspartyl proteases, and only a small part of the activity could be caused by some serine proteases.

Induction of adult diapause in Pyrrhocoris apterus L. by short cold exposure.

The ripening of ovaries in the females of Pyrrhocoris apterus can be inhibited not only by short-day photoperiod but also by cold shocks during the first week of the adult life.Ovaries in a part of the females are prevented from ripening by transferring the bugs from 25° C and long-day photoperiod to substantially lower temperatures for 2 (or 4) days. The oviposition is inhibited at least for 3 weeks after the return to original conditions favourable for reproduction. This effect is achieved when cold treatment is combined either with darkness or with long day. A difference between 2 and 4 days of chilling was not recorded. The effect of cold exposure (evaluated in our experiments by the proportion of mature and immature females) depends on the temperature of the cold exposure and on the age of females at the time of transfer to cold. The incidence of immature females was higher when lower temperatures (+2 to +6° C) were used and when females were transferred to cold early (0-2 days) after the adult moult.