Abdominal movements, heartbeats and gas exchange in pupae of the Colorado potato beetle, Leptinotarsa decemlineata

Abstract

Summary The rhythms of abdominal movements, heartbeats and gas exchange in the pupae of Leptiontarsa decemlineata (Say) were recorded simultaneously using an electrolytic respirometer and infrared gas analyser, both combined with contact thermography. Abdominal pulsations and heartbeat occurred periodically with little variance among individuals. The abdominal pulsations and heartbeat pauses varied individually within large limits, with the frequency of abdominal pulsations being six to seven times lower than that of the heart pulses. A proportion of the pupae (20%) showed discontinuous gas exchange with large, actively ventilated CO2 bursts, whereas others (≈ 25%) exhibited continuous regular microcycles (flutter) with abrupt intake of air into the tracheae before discrete microbursts of carbon dioxide. The abdominal pulsations exerted only a minor influence on ventilation during the microcycles. More than 90% of the bursts of abdominal movement coincided with a series of forward directed heartbeats, but interspersed between the bouts of abdominal movement commonly two to three heartbeat pulses were observed that were not associated with abdominal movements. A period of abdominal movement associated with a heartbeat pulse was commonly initiated by one or two vigorous strokes of abdominal rotation.

Dynamic mechanical oscillations during metamorphosis of the monarch butterfly

“…Examining the heart organ in the 60, 80 and 100%D stages (100%D indicates a pupa that emerged on the same day as the MRI image), it is clear that the heart becomes approximately 52 per cent thinner and approximately 15 per cent longer during development. Very little work has been done to characterize the development of the D. plexippus heart during metamorphosis, but the beating frequencies and BBs which we observe are highly consistent with other species (Gerould 1929;Slama 2000Slama , 2003;Smits et al 2000;Tartes et al 2000;Slama & Neven 2001;Slama & Farkas 2005). The MRI reveals that the late-stage heart is composed of denser muscle, consistent with the observations in other insects (Gerould 1929).…”

“…The spectrogram displays a maximum principal frequency at 0.52G0.03 Hz, which has several overtones (figure 3b). The periodic motions (figure 3c) are characteristic of a heartbeat (Gerould 1929;Slama 2000Slama , 2003Smits et al 2000;Tartes et al 2000;Slama & Neven 2001;Slama & Farkas 2005) and their frequency was observed to increase and decrease in amplitude during the BB (figure 3d ). The next stages of development 50-75%D and 75-83%D (figure 3e,f ) display very Mechanical oscillations of monarch butterfly A. E. Pelling et al 31 similar characteristics to the 0-50%D stage except they have two and three BBs per 2 hour period, respectively.…”

“…The heart organ is generally considered to be the abdominal part of the dorsal vessel that runs along the axis of the body (Slama 2000) and consists of a series of pumps (Snodgrass 1935). The heart drives the haemolymph around the body in an open circulatory system and is known to exhibit heartbeat reversal, changes in mechanical pressure, consumption and release of O 2 /CO 2 and fluctuations in temperature (Gerould 1929;Slama 2000Slama , 2003Smits et al 2000;Tartes et al 2000;Slama & Neven 2001;Slama & Farkas 2005). Based on the micromechanical phenomena observed in this study, we propose that the heart remains functionally intact even though massive structural development occurs during metamorphosis.…”

Interrelations of gas exchange cycles, body movements and heartbeats in the foragers of bumblebee Bombus terrestris (Hymenoptera: Apidae) at low temperatures

“…Metabolic rate, discrete CO2 releases and body movements were recorded by means of an electrolytic differential microres pirometer, where the consumed oxygen was replaced continu ously by adjusting the level according to pressure changes in the insect chamber (for more details see Kuusik et al, 1991Kuusik et al, , 1996Tartes et al, 1999Tartes et al, , 2000. In the present modification of this res pirometer, standard plastic tubes (Eppendorf, volume of 1.5 ml) were used as insect chambers, and were connected to the respirometric system by rubber tubing (inner diameter 0.5 mm).…”

“…Using a personal com puter the mean metabolic rate was calculated by averaging data over a longer period involving at least 3 DGCs (see Tartes et al, 2000).…”