Inorganic elements in the fat bodies of Diatraea saccharalis (Lepidoptera: Crambidae) larvae parasitized by Cotesia flavipes (Hymenoptera: Braconidae)

Abstract

Koinobiont parasitoids use several strategies to regulate the host's physiological processes during parasitism. Although many aspects of host-parasitoid interactions have been explored, studies that attempted to assess the effects of parasitism on the availability of inorganic elements in the host are virtually nonexistent. Therefore, we aimed to evaluate the effects of parasitism on the concentrations of inorganic elements in the fat bodies of larvae of Diatraea saccharalis (Lepidoptera: Crambidae) during the development of the parasitoid Cotesia flavipes (Hymenoptera: Braconidae), by using total reflection X-ray fluorescence (TXRF). TXRF analysis allowed comparisons of the changes in the availability of the elements P, S, K, Ca, Cr, Fe, Ni, Cu, and Zn in the fat body tissues of D. saccharalis larvae parasitized by C. flavipes. Overall, the concentration of inorganic elements was higher early in parasitoid development (1 and 3days after parasitism) compared to non-parasitized larvae, but much lower towards the end of parasitoid development (7 and 9days after parasitism). Ca, K, and S were reduced after the fifth day of parasitism, which affected the total abundance of inorganic elements observed in the fat bodies of the parasitized hosts. The regulatory mechanisms or pathological effects related to the observed variation of the host inorganic elements induced by the parasitoid remain unknown, but there might be a strategy to make these elements available to the parasitoid larvae at the end of their development, when higher metabolic activity of the host fat body is required to sustain parasitoid growth. The observed variation of the host's inorganic elements could also be related to the known effects of parasitism on the host's immune response.

Spatial Distributions of Inorganic Elements in Honeybees (Apis mellifera L.) and Possible Relationships to Dietary Habits and Surrounding Environmental Pollutants

“…A balance between P, Ca, K, Na, S, and Mg ions is crucial in regulating the activity level of ATPase . This biochemistry is likely responsible for the quite comparable distribution patterns of the elements P, S, and Mg. A detailed study of the inorganic elements found in the fat bodies of insects has been reported previously . The hot zones of the P element appear to be associated with the places requiring a higher energy demand for ATP activity; that is, higher energy is required for metabolism in the alimentary canal, the chest muscles that power the wings, and the heavy activities of the brain.…”

“…8 This biochemistry is likely responsible for the quite comparable distribution patterns of the elements P, S, and Mg. A detailed study of the inorganic elements found in the fat bodies of insects has been reported previously. 9 The hot zones of the P element appear to be associated with the places requiring a higher energy demand for ATP activity; that is, higher energy is required for metabolism in the alimentary canal, the chest muscles that power the wings, and the heavy activities of the brain. The reasons behind the distribution pattern of Ca element being different from that of the P, Mg, and S elements remains unclear, but one possible explanation might be the fact that the Ca element also participate in the programming of apoptosis; that is, pronounced Ca element accumulation occurred along with the preparation of a larva transforming into a pupa.…”

Atomic spectrometry update-X-ray fluorescence spectrometry

“…In several biological applications TXRF or SRXRF were used as analytical techniques. The effects of parasitism on the concentration of inorganic elements in the fat bodies of larvae of Diatraea saccharalis during the development of the parasitoid Cotesia flavepes was evaluated by Pinheiro et al 502 using TXRF. Overall, the concentration of inorganic elements was higher early in parasitoid development (1 and 3 days after parasitism) compared with non-parasitised larvae, but much lower towards the end of parasitoid development (7 and 9 days after parasitism).…”

Macro-elements in the hemolymph of adult Euschistus heros (Fabr.) (Hemiptera: Pentatomidae) treated with pyriproxyfen

“…In Diatraea saccharalis Fabr. (Lepidoptera: Crambidae) larvae the concentration of macro-elements such as phosphorus (P), sulfur (S), potassium (K) and calcium (Ca) in fat body samples increased after parasitism by Cotesia flavipes Cameron (Hymenoptera: Braconidae) (Pinheiro et al, 2010a). In the same insects, a morphological study suggested that ionic imbalance may be associated with alterations in basal labyrinth of columnar midgut cells, as well as in cytoplasm T projections that contain mitochondria in the chamber of midgut goblet cells (Pinheiro et al, 2010b); it could also be related to the presence and alteration of spherites in all four types of midgut epithelial cells (Pinheiro et al, 2008).…”