Mouthpart Structure, Feeding Mechanisms, and Natural Food Sources of Adult Bactrocera (Diptera: Tephritidae)

Abstract

Mouthpart structure, feeding mechanisms and natural sources of food of the adults of four species of Bactrocera fruit flies (Tephritidae: Diptera) endemic to Queensland, viz. Bactrocera tryoni (Froggatt), Bactrocera jarvisi (Tryon), Bactrocera cacuminata (Hering) and Bactrocera cucumis (French), were stnjdied. When exposed to dry food, adults always regurgitated fluid from their crop to liquefy and dissolve the food substrate. Regurgitated liquids and dissolved food were then reingested but only through fine micropores (< 0.5 ^jim) on the feeding tubules (pseudotracheae). Large particles (> 0.5 | jLm) were prevented from being ingested by prestomal spines, which project across the oral opening, as well as by t±ie flexure of tiie oral lobes to form the prestomal sulcus. The intake of food by Bactrocera adults was thus restricted to fluids and firuit fiy-type bacteria. Larger particles, such as pollen grains, fungal spores and even yeasts, commonly found on the surfaces, were excluded by the micropores.Studies on the infiuence of diet on the development of the gonads, accessory glands and ability to mate in B. tryoni provided previously unavailable information on the development of the accessory glands in both sexes, and the erecting and pumping organ of males in relation to diet. The current view, that male flies do not require proteins for normal sexual activity, is inaccurate. Although males deprived of proteins could mate and inseminate females, they had a smaller erecting and pumping organ, and were less competitive compared with males fed proteins.Systematic field observations on the diet pattern of activity of adult B. tryoni and B. cacuminata in their native environments: (i) identified the major feeding and mating sites of B. tryoni and B. cacuminata; (ii) established that adult flies fed primarily on the surfaces of host fruits; and (iii) confirmed the importance of the host plant as a centre of activity of tropical tephritids.

Mouthpart conduit sizes of fluid-feeding insects determine the ability to feed from pores

“…As shown in figure 4d, the expelled fluids make it possible to connect the liquid inside the small substrate pores to the liquid bridge inside the food canals via a capillary conduit. Our observations supplement previous findings that flies and butterflies expel fluids while feeding on dry or porous surfaces [13,35,36]. For unfed insects, the measured limiting pore sizes are approximately equal to the distal mouthpart diameters and show little dependence on the proximal dimensions ( figure 3).…”

“…Their ability to feed on a wide variety of fluids, such as nectar, blood, sap flows, honeydew and juices on carrion, rotting fruit and dung [6][7][8][9][10], probably contributed to their massive radiation by providing opportunities to enter new adaptive zones [11]. Both groups have mouthparts (proboscises) that are conceptually a conduit with modified distal parts that support fluid uptake [12][13][14][15].…”

Functional, evolutionary and ecological aspects of feeding-related mouthpart specializations in parasitoid flies

“…Elzinga & Broce, 1986;Vijaysegaran et al, 1997), and it is clear that the various components are very variable, even amongst the Muscomorpha (Elzinga & Broce, 1986). Elzinga & Broce, 1986;Vijaysegaran et al, 1997), and it is clear that the various components are very variable, even amongst the Muscomorpha (Elzinga & Broce, 1986).…”

“…In its basic mode, the proboscis is used to mop up and/or suck up liquids (Graham-Smith, 1930;Vijaysegaran et aL, 1997), either as liquid food (nectar, honeydew), or as solid material dissolved/suspended in salivary secretions. Studies of the functioning of dipteran mouthparts are relatively rare in the literature (Graham-Smith, 1930;Schiemenz, 1957;Schuhmacher & H o h a n , 1982;Vijaysegaran et al, 1997) and there have been many wild guesses as to how the various parts operate, especially in feeding from flowers or on honeydew.…”

Effect of Probiotic Adult Diets on Fitness Components of Sterile Male Mediterranean Fruit Flies (Diptera: Tephritidae) Under Laboratory and Field Cage Conditions

“…As Hendrichs (2000) notes, the importance of natural food sources, including bacteria, on male reproductive success and Þeld performance remains an aspect of fruit ßy behavioral ecology that is poorly understood. Tephritid ßies harbor microorganisms in their alimentary canal, and the presence of ectocellular enteric bacteria has been documented for a range of species in this family (Rossiter et al 1983, Howard et al 1985, Drew and Lloyd 1989, Howard 1989, Daser and Brandl 1992, Vijasegaran et al 1997. These symbiotic microorganisms are harbored in the esophageal bulb, crop, and midgut caeca of fruit ßies (Douglas and Beard 1996).…”