Fluid intake rates in ants correlate with their feeding habits

Paul, Jürgen; Roces, Flavio

doi:10.1016/s0022-1910(03)00019-2

Cited by 69 publications

(83 citation statements)

References 44 publications

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“…Foraging energetics of a nectar-feeding ant measurement of crop load not feasible. For the other, more attractive sucrose concentrations, no accumulation occurred, since the highest flow rate assayed lies well below the maximal intake rates of Camponotus rufipes (Schilman and Roces, 2003;Paul and Roces, 2003). Comparing 5 and 30% sucrose solution, feeding times significantly depended on flow rate (F 2,71 =54.495, P<0.001), but not on sucrose concentration (F 1,71 =0.816, NS).…”

Section: Metabolic Rate As a Function Of Nectar Flow Ratementioning

confidence: 89%

Foraging energetics of a nectar-feeding ant: metabolic expenditure as a function of food-source profitability

Schilman

Roces

2006

Journal of Experimental Biology

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SUMMARY We examined the quantitative relationship between the energetic costs and benefits of nectar collection by nectar-feeding ants, Camponotus rufipes. In the laboratory, individual workers were trained to visit an artificial feeder that provided a sucrose solution of 1%, 5%, 10%, 30% or 50%at controlled flows, in a similar span range to those observed in natural nectar sources. We measured foraging times, nectar loads collected, and CO2 production during actual feeding, as an indication of the energy expenditure for a single forager. Results show an increase in individual metabolic rates with increasing flow rate of sugar solution, but no dependence on sucrose concentration. This increase in metabolic expenditure does not depend on the crop load attained while feeding, as intuitively expected, and is therefore a result of an increased activity brought about by the food-source profitability experienced by the forager. The energy gained during collection of sugar solution is always higher than the energy spent by the ant. Even with a food source of lower quality than a natural source, the ants gain ca. tenfold of what they spend. Based on a simplified model, we calculated that foragers of C. rufipes could travel from 0.5 to 9 km with the energy gained in a single foraging trip only. These results suggest that decreasing foraging time is more important than increasing individual energetic efficiency when workers of the nectar-feeding ant C. rufipes decide to stop drinking and return to the nest with partial crop loads.

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Section: Metabolic Rate As a Function Of Nectar Flow Ratementioning

confidence: 89%

Foraging energetics of a nectar-feeding ant: metabolic expenditure as a function of food-source profitability

Schilman

Roces

2006

Journal of Experimental Biology

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“…Although predictions of the Daniel et al model (Daniel et al, 1989) concur with optima derived from laboratory feeding trials with butterflies (Boggs, 1988;May, 1985;Pivnick and McNeil, 1985), hawkmoths (Josens and Farina, 2001), orchid bees (Borrell, 2004), bee-flies (Kingsolver and Daniel, 1995), and ants (Paul and Roces, 2003), the predicted relationship between the pressure drop produced in the cibarium and fluid flow through the proboscis has never been experimentally validated (Kingsolver and Daniel, 1995). The relationship between pressure and flow depends crucially on values of V max and T 0 , which are not easily measured.…”

Section: Introductionmentioning

confidence: 91%

Mechanics of nectar feeding in the orchid beeEuglossa imperialis: pressure, viscosity and flow

Borrell

2006

Journal of Experimental Biology

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SUMMARY The orchid bee Euglossa imperialis sucks nectars through a slender proboscis. I tested how nectar properties influence this suction pressure and whether ambient air pressure sets the upper limit for suction feeding. Nectar intake rate was measured as a function of sucrose concentration (5-75% w/w),nectar viscosity (2-80 mPa s), and ambient pressure (101-40 kPa). Intake rate declines from about 1.2 μl s-1 to 0.003 μl s-1 as sucrose concentration increases from 15% to 65% sucrose. When sucrose concentration is held at 25% while viscosity increases from 2 to 80 mPa s,intake rate declines. When viscosity is held at 10.2 mPa s (the viscosity of 50% sucrose) while sucrose concentration increases from 5% to 50%, intake rate remains constant. Intake rate was limited by a reduction in ambient pressure at all nectar concentrations. Assuming a rigid proboscis, the Hagen-Poiseuille equation suggests that suction pressure increases with viscosity from 10 kPa at 5% sucrose to 45 kPa at 65% sucrose. However, because intake rate declined by the same fraction under hypobaria (40 kPa) at all sucrose concentrations,the euglossine bee proboscis may be better described as a collapsible tube:expanding or collapsing depending on the flow rate, the pressure gradient along the proboscis, and circumferential forces imposed by the proboscis walls.

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“…1. Optimal sugar concentrations for various nectar feeders (2,5,8,9,12,16,18,22,(24)(25)(26)(27)(28)(29)(30)(31). The optimal concentration is that for which the energy intake rate is highest based on drinking rates measured at various nectar concentrations in a laboratory setting.…”

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confidence: 99%

“…Nectar-feeding birds (e.g., hummingbirds* and sunbirds) employ capillary suction, in which capillary pressure drives flow along the tongue once its tip touches the nectar (3). Most bees (except orchid bees) and some ants ingest nectar by dipping their tongue into, then extracting it from, the viscous nectar (4,5). It is advantageous for creatures to ingest energy rapidly due to the threat of predation during feeding.…”

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confidence: 99%

Optimal concentrations in nectar feeding

Kim

Gilet

Bush

2011

Proc. Natl. Acad. Sci. U.S.A.

191

222

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Nectar drinkers must feed quickly and efficiently due to the threat of predation. While the sweetest nectar offers the greatest energetic rewards, the sharp increase of viscosity with sugar concentration makes it the most difficult to transport. We here demonstrate that the sugar concentration that optimizes energy transport depends exclusively on the drinking technique employed. We identify three nectar drinking techniques: active suction, capillary suction, and viscous dipping. For each, we deduce the dependence of the volume intake rate on the nectar viscosity and thus infer an optimal sugar concentration consistent with laboratory measurements. Our results provide the first rationale for why suction feeders typically pollinate flowers with lower sugar concentration nectar than their counterparts that use viscous dipping.biomechanics | biocapillarity | optimal concentration M any insects and birds feed primarily or opportunistically on floral nectar. There are three principal techniques employed by nectar feeders: active suction, capillary suction, and viscous dipping. Lepidopterans (e.g., butterflies and moths) employ the former, sucking nectar through their probosci, along which a pressure gradient is generated by cibarial muscles (1, 2). Nectar-feeding birds (e.g., hummingbirds* and sunbirds) employ capillary suction, in which capillary pressure drives flow along the tongue once its tip touches the nectar (3). Most bees (except orchid bees) and some ants ingest nectar by dipping their tongue into, then extracting it from, the viscous nectar (4, 5). It is advantageous for creatures to ingest energy rapidly due to the threat of predation during feeding. Optimal conditions might thus be sought to maximize their energy intake rate. While the sweetest nectar offers the greatest energetic rewards, the exponential increase of viscosity with sugar concentration (2) also makes it the most difficult to transport. We here rationalize the different optimal concentrations reported for the different drinking strategies by developing a dynamic model for viscous dipping and comparing it to existing models of suction feeding. Our viscous dipping model indicates an optimal sugar concentration of 52%, which is higher than that for suction feeding, 33%. This result suggests a rationale for the fact that the nectar concentration of flowers pollinated by viscous dippers such as bees (35%) is typically higher than that of those pollinated by suction feeders such as hummingbirds or butterflies (20-25%) (6).The sugar concentration that maximizes energy intake rate has been evaluated for a variety of nectar feeders in previous experimental studies (Fig. 1). Careful consideration of all of these results indicates that this so-called "optimal concentration" depends exclusively on feeding mechanism but not on body size, quantity of intake, or species. Roughly speaking, the optimal concentration for active or capillary suction feeders is 30-40% while that for creatures using viscous dipping is 50-60%. Optimal sugar concentrations for s...

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Fluid intake rates in ants correlate with their feeding habits

Cited by 69 publications

References 44 publications

Foraging energetics of a nectar-feeding ant: metabolic expenditure as a function of food-source profitability

Foraging energetics of a nectar-feeding ant: metabolic expenditure as a function of food-source profitability

Mechanics of nectar feeding in the orchid beeEuglossa imperialis: pressure, viscosity and flow

Optimal concentrations in nectar feeding

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