Papers by Francesco Andrietti
acta ethologica, 2010
Strategies adopted by parasitoids and kleptoparasites co-evolve with the defensive adaptations of... more Strategies adopted by parasitoids and kleptoparasites co-evolve with the defensive adaptations of their hosts, and vice-versa. Hedychrum rutilans and Hedychrum nobile are brood parasites of, respectively, Philanthus triangulum and Cerceris arenaria, two digger wasps that share most aspects of their nesting biology (solitary females dig aggregated nests in the ground and mass-provision the brood with paralyzed insects). We tested the
Figure 1. A Leucophora personata female, paint-marked on its thorax, waits for the exit of a host... more Figure 1. A Leucophora personata female, paint-marked on its thorax, waits for the exit of a host bee (a) and then enters its nest (b). Note the head directed towards the nest entrance in (a).
Figure 2. Seasonal activity of the parasitic flies Bombylius fimbriatus and Leucophora personata ... more Figure 2. Seasonal activity of the parasitic flies Bombylius fimbriatus and Leucophora personata and their host bee Andrena agilissima in 1997. For the Diptera, the left ordinate gives the total number of observations, whilst for A. agilissima the right ordinate gives the number of marked bees that were observed on one day. Rainy days, when neither flies nor bees were active, are omitted.
Echinoderm Research, 2020
... of regular sea-urchins: structural organization and mechanical properties in Paracentrotus li... more ... of regular sea-urchins: structural organization and mechanical properties in Paracentrotus lividus MD Candia Carnevali, F. Bonasoro, F. Andrietti & G. Melone Department of ... The hlstofluorescencemicro-scopy shows at this level a wide-spread diffusion of yellow fluore-scence. ...
Fisiologia.-Variances in spectral analysis of membrane noise W. Nota di FRANCESCO ANDRIETTI e CAR... more Fisiologia.-Variances in spectral analysis of membrane noise W. Nota di FRANCESCO ANDRIETTI e CARLA CANEGALLO, presentata (**) dal Corrisp. V. CAPRARO. RIASSUNTO.-Le fluttuazioni di conduttanza di un modello di canale del potassio di una fibra muscolare che segue una cinetica di Hodgkin e Huxley sono state analizzate attraverso l'analisi spettrale indiretta. Sono state confrontate due diverse stime della densità spettrale è le loro rispettive varianze: quella della prima stima considerata è già nota, mentre quella della seconda stima è stata ricavata da noi nelle medesime ipotesi (distribuzione normale). I risultati teorici sono stati confrontati con quelli ottenuti mediante simulazione numerica del processo stazionario in questione. Sono state sviluppate alcune considerazioni sul significato del nostro lavoro per quanto riguarda Tanalisi del rumore di membrana: il miglior uso delle stime spettrali, sia dirette che indirette, la lunghezza delle sequenze dei segnali di entrata, Putilizzazione di « finestre » di vario genere.
Journal of Insect Behavior, 1999
Andrena agilissima is a bee that nests on sloped or vertical earth walls. Data from 3 years of fi... more Andrena agilissima is a bee that nests on sloped or vertical earth walls. Data from 3 years of fieldwork presented here show that this species is communal and uses the same nesting site for many years. On an earth wall on Isola d'Elba (Tuscany, Italy), covered with many bee nest entrances, we studied an aggregation of Andrena agilissima to determine
ABSTRACT The brood of ground-nesting Hymenoptera is often the victim of parasitic flies. We obser... more ABSTRACT The brood of ground-nesting Hymenoptera is often the victim of parasitic flies. We observed the behavioural relationships between the sand wasp Bembix sp. near capensis Lepeletier 1845 (Hymenoptera Crabronidae) and its brood parasite Craticulina fimbriata Bezzi 1911 (Diptera Sarcophagidae) in Ouagadougou (Burkina Faso). Craticulina fimbriata females performed satellite flights in order to reach the nests of B. sp. near capensis, their frequency being higher when host provisioning activity was higher. The wasp made evasive manoeuvres when followed by the fly while coming back to the nest both with and without prey. Evasive flights effectively reduced the number of visits of the satellite fly into the nest. Wasps which closed their nest before every departure rather than leaving the nest entrance open seemed to suffer a lower frequency of satellite fly visits into the nest. Thus, both evasive manoeuvres and nest closure play a role in reducing the contact between C. fimbriata and the wasp provisions. We also recorded a rare phenomenon in digger wasps. About 30% of provisioning trips were followed by the immediate exit of the prey from the nest, showing that many of them were not paralysed. Prey escaped throughout the daily provisioning period, but less from nests that were usually closed by the wasps. Moreover, a relationship emerged between the frequency of escaping prey and satellite fly activity. Possible explanations of this phenomenon are discussed.
Pathobiology, 1993
A theoretical model of a cotransport system in plasma membrane vesicles has been utilized for the... more A theoretical model of a cotransport system in plasma membrane vesicles has been utilized for the analysis of the Na(+)-dependent L-alanine transport into plasma membrane vesicles purified from Yoshida ascites hepatoma (AH 130) cells in the exponential and stationary phases of growth. The analysis was performed by comparing the experimental curves with computer simulations. In particular we considered the differences in alanine uptake observed in the two preparations and we tried to ascribe them to changes of some parameters of the transport model. The simulations indicate that sodium, alanine or water passive permeability changes cannot explain the experimental data which are consistent, on the contrary, with a relevant enhancement of the Vmax of the transport agency. The involvement of the membrane electrical potential difference is also discussed.
Journal of Mathematical Biology, 1986
A linear two-dimensional model of a flow system for solute and fluid transport in intercellular s... more A linear two-dimensional model of a flow system for solute and fluid transport in intercellular spaces has been obtained by using the so called “isotonic convection approximation”, already employed in the one-dimensional case (Segel (1970)). This is equivalent to ignoring the convective components in the relevant differential equation. The solutions found by means of the eigenfunctions of a Sturm-Liouville system
Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology, 1998
ABSTRACT The jaw apparatus, or lantern, of sea-urchins contains five pairs of retractor and protr... more ABSTRACT The jaw apparatus, or lantern, of sea-urchins contains five pairs of retractor and protractor muscles which are responsible for lantern displacement. Using intact retractor or protractor groups, the force-length relations of these muscles were compared in two taxonomically distant species, Paracentrotus lividus and Stylocidaris affinis. The total contractile forces generated by the muscles can be resolved into vertical and horizontal components. It was found that the vertical component of the retractors is maximal at a lantern position which is significantly lower (i.e. more protruded) in Paracentrotus than in Stylocidaris. Total forces generated by the retractors were in both species maximal at or above the lantern `resting positions'. In Paracentrotus alone, the total force-displacement curves tended to be bimodal. It is hypothesized that the retractors of Paracentrotus contain two populations of muscle fibres, one adapted for jaw opening and one for lantern retraction. No significant differences in the properties of the protractors of the two species could be identified. The lantern of Paracentrotus is more mobile than that of Stylocidaris and is able to exploit a wider range of food sources. This investigation has shown that the force-length relations of the lantern muscles match their differing working conditions.
Sociobiology, 2006
Résumé/Abstract Nest is an important resource for fossorial Hymenoptera, and it becomes very limi... more Résumé/Abstract Nest is an important resource for fossorial Hymenoptera, and it becomes very limiting in those species that rarely dig new burrows but commonly re-use existing (conspecific) ones. A population of the solitary digger wasp Cerceris arenaria ( ...
Biological Cybernetics, 1977
Neural transmitters can generally exist in several states: stored, released, in combination with ... more Neural transmitters can generally exist in several states: stored, released, in combination with receptors, and recycling to storage. A set of equations is proposed and analyzed for such a system. We have considered boundedness and stability of solutions, and we have discussed physiological effects such as response saturation and adaptation. We have investigated the effects o f the model parameters on system behavior and we have indicated how the model can be extended to include phenomena such as transmitter mobilization, modulation if its release and receptor desensitization.
Biochimica et Biophysica Acta (BBA) - Biomembranes, 1990
A theoretical analysis of the time course of a ternary cotransport system in membrane vesicles ha... more A theoretical analysis of the time course of a ternary cotransport system in membrane vesicles has been developed by extending previous work (Weiss, S.D. et al. (1981) J. Theor. Biol. 93, 597-608; Heinz, E. and Weinstein, M. (1984) Biochim. Biophys. Acta 776, 83-91). It has been assumed that the translocation of the carrier is the rate-limiting step of the transport process. Our approach includes, in particular, the presence of isotope tracer fluxes and the generalization to the case when many solutes share the same carrier. The situation when the tracer and the solute behave differently, as in the countertransport case, is stressed. Also, the interaction of two different solutes, internal and external to vesicles, is considered. Other points regard the analysis of the solute binding to the membrane vesicles, the influence of water permeability and the possible asymmetry of the transport system. In the Appendix, the assumption of no net translocation of all carrier species is discussed.
Biochimica et Biophysica Acta (BBA) - Biomembranes, 1991
A critical analysis of the use of membrane vesicles in the study of cotransport processes is pres... more A critical analysis of the use of membrane vesicles in the study of cotransport processes is presented. Transport experiments were simulated according to two different models, stressing those conditions that seemed more relevant in affecting the measurements. In particular, we observed that the experimental lima x values were underestimated. This underevaluation depended on the incubation time employed to measure the initial uptake rate and on the time necessary to wash the vesicles. Also the temperature and the composition of the washing solution, together with the Qt0 of the transport process taken into consideration, had a consistent influence on the uptake. All the above mentioned effects were affected by the vesicle volume: the smaller the volume, the greater the understimata of the uptake. This theoretical analysis underlines, on the one side, that the experimental data should be interpreted with some caution, on the other, that the examined procedure allows an internal check of its validity by adopting suitable simulations of the experiments. The use of the presented models a~ a tool for the planning and the critical analysis of the experimental results is suggested.
South African Journal of Marine Science, 2002
Some behavioural aspects of the reproductive biology of Megaselia andrenae Disney, a kleptoparasi... more Some behavioural aspects of the reproductive biology of Megaselia andrenae Disney, a kleptoparasite of the communal bee Andrena agilissima (Scopoli), were investigated at the nesting site of its host at Isola d'Elba (Italy). The scuttle fly mates more often in the early afternoon, which coincides with the period when the provisioning flights of its host are more frequent. The presence of the flies at the host nesting site, either in copula or single, is lower in the morning. In general only the females enter the host nests immediately after a mate, in a few cases closely followed by the males. When leaving the nest, females refuse to mate again with the males waiting outside. Observations on the ovaries of the females revealed no differences, either in the number of eggs or in the length of the most mature egg, between the individuals collected in copula or when flying alone. The species is sexually dimorphic, the females being larger than males. Male size does not seem to influence the females choice for mating.
Figure 4. The frequency of observations of the parasitic flies Leucophora personata (n511 observa... more Figure 4. The frequency of observations of the parasitic flies Leucophora personata (n511 observations) and Megaselia andrenae (n52384 observations) across a nesting aggregation of their host bee Andrena agilissima in relation to variation in the density of host nests.
Figure 3. Daily activity patterns of the parasitic flies Bombylius fimbriatus and Leucophora pers... more Figure 3. Daily activity patterns of the parasitic flies Bombylius fimbriatus and Leucophora personata and their host bee Andrena agilissima in 1997. For the Diptera, the left ordinate gives the total number of observations per hour, whilst for A. agilissima the right ordinate gives the number of marked bees that were observed to enter nests over the same time period.
Echinoderm Research 1991, 2020
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Papers by Francesco Andrietti