Feeding behaviour in response to blood fractions and chemical phagostimulants in the black-fly, Simulium venustum

ABSTRACT. Wild-caught black-flies ( Simulium venustum Say complex) were presented with diets at 37°C in an artificial feeding apparatus. Washed human red cells resuspended 1:1 in Ringer solution were potent phagostimulants, causing 89% of flies to gorge. Whole plasma was more potent (32% gorging) than platelet-poor plasma (2%). The ED₅₀ for red cells was 3.5%. Although ADP, contained in high-concentration in platelets, was confirmed as a more potent phagostimulant than ATP (ED₅₀ of 5πM V. 12μM), red cells were clearly more phagostimulatory than platelets, and with a potency more than adequate to trigger gorging in vivo. A high response to the ATP analogues, β, γ-methylene ATP and adenine phosphosulphate, supports the view that the phosphate chain is relatively unimportant in determining nucleotide potency to simuliids. The compounds phytic acid and 2,3-disphosphoglycerate, potent stimulants to Rhodnius prolixus , produced only moderate and no response, respectively at 1 mM; 5-hydroxytryptamine, another major constituent of platelets, also produced only a moderate response. Only flies caught while showing a characteristic probing behaviour would subsequently probe and feed in vitro; this 'blood-feeding mode' rapidly disappeared in the absence of stimuli eliciting actual probing, but for flies in this state a small temperature rise was sufficient stimulus for probing.     

ATP analogues and other phosphate compounds as gorging stimulants for Rhodnius prolixus

Five analogues of ATP and six other non-nucleotide compounds with phosphate groups were tested as gorging stimulants for second-instar larvae of Rhodnius prolixus to determine the importance of the phosphate chain. Only molecules with terminal phosphate groups were potent. Insertion of an imido group (5′-Adenylylimidodiphosphate, AMP-PNP) or a methylene group (β, γ-Methylene adenosine 5′-triphosphate, AMP-PCP) between the β and γ phosphates of ATP reduced the potency compared to ATP by ratios of 1.8 and 25.5, respectively. Substituting ribose (Adenosine 5′-diphosphoribose, AMP-PR) for the γ phosphate group or an amidate or a sulphate group (Adenosine 5′-phosphoramidate, AMP-N; Adenosine 5′-phosphosulphate, AMP-S) for the β and γ phosphate groups of ATP resulted in a complete loss of stimulatory activity.Some non-nucleotide phosphate compounds were potent phagostimulants. Pyrophosphate with an ED₅₀ of 64 μM had a potency ratio compared with ATP of 1:17. Methylene diphosphonic acid (ED₅₀ 680 μM) and even single phosphate ions (ED₅₀ 2.5 mM) had substantial potency. Two isomers of phosphoglyceric acid differ greatly in their ability to stimulate gorging; 2-PGA was active (ED₅₀ 160 μM) whereas 3-PGA had almost no activity.A summary of known phagostimulants to R. prolixus supports the hypothesis that ATP-like gorging stimulants act by forming a temporary binding to 3 sites on a receptor protein in the membrane of the chemosensory cell. The amino group on C₆ of adenine, the OH group on C₂ of ribose and the terminal phosphate group(s) determine potency, presumably by determining binding affinity. However, only the phosphate group appears essential to the chemosensory process.     

Effect of ATP analogues on the gorging response of Aedes aegypti

ABSTRACT. The ATP analogues adenylylimidodiphosphate and adenylylmethylenediphosphate are 3–5-fold more effective than ATP as gorging stimulants for Aedes aegypti. This increased potency is not due to the fact that the two analogues are not hydrolysed by the mosquito salivary apyrase, but most likely to their greater affinity to the mosquito gustatory receptor protein. The analogues 2'd ATP and 3'd ATP are about half as potent as ATP, while 2',3'-dideoxyadenosine triphosphate is 10-fold more potent than ATP in evoking the gorging response. It is proposed that removal of both hydroxyl groups eliminates binding of the stimulant at the ribose moiety, thus allowing the molecule greater freedom to rotate and bind more effectively to its two other binding sites at the amino group on the purine and at the terminal phosphate. Our data demonstrate that ATP activates the gorging response of Ae.aegypti merely by binding to its receptor protein and is not required as an exogenous source of energy. Gorging response to ATP is competitively inhibited by novobiocin.     

Sensitivity of the mosquito Aedes aegypti (Culicidae) labral apical chemoreceptors to phagostimulants

The feeding of Aedes aegypti (L.) on blood and nectar is induced by phagostimulants: adenine nucleotides and sugars respectively. This work examines the responses of the four chemoreceptor cells in the labral apical sensilla to these phagostimulants. The apical chemoreceptors can detect the presence of adenine nucleotides. This part of the response is in good agreement with the gorging behavior. The output of the chemoreceptors cannot distinguish among different adenine nucleotides or among their concentrations (0.01-1 mmol/l), whereas gorging behavior is affected by the identity of adenine nucleotides and by their concentrations. Hence the gorging behavior cannot be driven by the output of these chemoreceptors alone. To the presence of adenine nucleotides Cell 2 was the only cell that responded with high frequencies, while the response of Cell 4 was almost abolished. The response of Cell 2 to ATP depended on the mosquito's physiological state. This dependence accorded well with the gorging behavior; Cell 2 responded with a higher frequency to ATP in the gorging state, than when not in a gorging state. The responses to sucrose and fructose constituted the only case recorded in which all these chemoreceptors failed to respond. This depression of response implies that other chemoreceptors must be present as sugar detectors.     

Feeding responses of the horsefly, Tabanus nigrovittatus, to physical factors, ATP analogues and blood fractions

ABSTRACT. Wild-caught female horseflies, Tabanus nigrovittatus Macq. (Diptera: Tabanidae), were presented solutions of seven analogues of ATP in 0.15 m NaCl, or various blood fractions, either as free liquids at 22 or 38C or covered with a Parafilm M membrane at 38C. Warming the diet, so that it can stimulate the insects' heat receptors, or presenting it warmed and covered with a membrane, which the flies can pierce and thus deploy their mouthparts as they would when blood-feeding, enhances the response to gorging stimulants. ADP (ED₅₀ 45 μM) was the most potent chemical phagostimulant. There were no significant differences between the potencies of AMP, A(TETRA)P, AMP-PCP, AMP-PNP or AMP-S, which were 3.5-5 times less potent than ADP. Cyclic AMP had no phagostimulatory activity at concentrations of 400 or 1000 μM. The ED₅₀ for washed red blood cells (RBC) in saline was 4.5% (one tenth the concentration found in blood). RBC-free plasma caused only 10% gorging but plasma with 0.5% RBC caused 61% gorging, indicating synergism between RBC and plasma.     

Chemosensory stimuli in feeding behavior of the leechHirudo medicinalis

The involvement of chemotherapy stimuli in the feeding behavior of the blood-sucking leech Hirudo medicinalis was investigated using a behavioral feeding test in which test solutions were encased in a highly permeable membrane and presented to the leech. Whole human blood or plasma at ambient temperature elicited the complete sequence of feeding behavior: probing, attachment, biting and ingestion. Spring water, 300 mM sucrose, or dialyzed plasma did not elicit any of these responses. Spring water warmed to 38 degrees C elicited probing and transient attachment but not ingestion. Thus, appropriate chemical stimuli were necessary for complete feeding behavior. A chemically defined artificial blood mix, containing the major components of low molecular weight found in blood, elicited all aspects of leech feeding behavior. Eliminating either NaCl or arginine from the mix resulted in complete loss of effectiveness. Moreover, a solution containing only NaCl (150 mM) and arginine (90 microM) was also an effective feeding stimulus. Thus, appropriate chemical stimuli are sufficient for complete feeding behavior. Neither NaCl nor arginine alone induced feeding although NaCl alone elicited probing. Sensory detection of blood was localized to a region of the dorsal lip that contains structures composed of ciliated, bipolar neurons, which are likely candidates as chemoreceptors. Surgical ablation of this region of the skin resulted in complete loss of ability to alert to, orient toward and ingest blood, while sham-operated controls fed normally. Substitution with other ions revealed specificity, with respect to both the cation and the anion, in the response to NaCl. Of the inorganic and organic cations tested, only Li+ substituted effectively for Na+. Of the inorganic and organic anions tested, only Br- was as effective as Cl-. Thus, the requirement for NaCl in leech feeding represents more than simply an ionic strength requirement or a requirement for Na+ ions and bears similarities to the chemosensory detection of NaCl in other species. Substitution with other amino acids and analogues for arginine revealed marked specificity in the feeding response to this compound as well. D-arginine at concentrations of up to 1000-fold greater than the effective threshold for L-arginine did not elicit ingestion, nor did other common L-amino acids, including the other basic amino acids histidine and lysine. Of the arginine analogues tested, only homoarginine and canavanine (in which all three functional groups of arginine are unchanged) were effective feeding stimulants.     

Feeding in Rhodnius prolixus: mouthpart activity and salivation, and their correlation with chanees of electrical resistance

Detailed observations were made of mouth part movements, salivation and ingestion in Rhodnius prolixus feeding on an artificial diet. Several events not previously described in blood-feeding Hemiptera were recorded; these included formation of a salivary ‘collar’, continuous salivation during probing, and sampling of diet prior to initiation of gorging. The events during feeding were analysed in detail and correlated with changes in electrical resistance between haemolymph and diet by recording both simultaneously on video-tape using a split-screen television technique.     

Feeding in Rhodnius prolixus: Increasing sensitivity to ATP during prolonged food deprivation

The percentages of third instar larvae of Rhodnius prolixus that would gorge on 4 × 10⁻⁶M ATP in 0·15 M NaCl were determined at various times from 15 to 140 days after a normal blood meal. As the time interval increased so did the proportion of insects that gorged, indicating an increasing sensitivity to the gorging stimulant. The relationship between sensitivity to ATP and the time elapsed since the previous blood meal is linear, sensitivity increasing by about 20 per cent of its value at day 15 every 10 days. This changing sensitivity may be related to a continuous metabolic activity such as depletion of food reserves; it does not appear to be affected by desiccation, and continues after all detectable remains of the last blood meal have been absorbed from the gut during the period 40 to 140 days after feeding.     

Feeding responses of the horsefly, Tabanus nigrovittatus, to phagostimulants

ABSTRACT. Wild caught horseflies, Tabanus nigrovittatus Macq. (Diptera, Tabanidae), were presented solutions of 0.15 MNaCl at 37°C containing various concentrations of ATP, ADP, AMP, adenosine, phytic acid or 2,3-diphosphoglycerate in an artificial feeding apparatus. The insects fed upward through a Para-film M® membrane. ADP (ED₅₀ 35 μM) was more potent than ATP (ED₅₀ 112 μM) and AMP (ED₅₀ 382 mUM). All of these diets were deposited in the midgut, an indication that the flies were in the 'blood feeding' mode. Adenosine caused only 23% gorging at 1 mM. Phytic acid caused only 10% gorging at 1 mM and 2,3-diphosphoglyceric acid had no activity at 0.6 mM. Flies would feed only in highly reflective cages under high levels of light intensity (1200–1500 lux) at the membrane surface.     

The interaction of taste and heat on the biting response of the tsetse fly Glossina fuscipes fuscipes

Abstract.Tsetse flies probe more on a heated surface with a trace of uric acid than on one without. Uric acid is one of the components of human sweat and it elicits spike responses from taste hairs on the flies' legs. In this paper it is examined how heat from the surface and taste interact to affect the biting behaviour of Glossina fuscipes fuscipes Newstead 1910 (Diptera: Glossinidae) over successive days of food deprivation. The biting behaviour consists of bouts of probing, both ambulatory and stationary, intercalated with short hops of flight. The number of bouts increases over successive days, whereas the average bout duration does not. Although uric acid alone could not induce the flies to probe, in combination with surface heat it affected the flies greatly. Average bout duration was two‐fold that on a heated surface not treated with uric acid. The frequency of bouts was not affected by uric acid. These experiments and auxiliary ones on mechanoreceptive input and odours lead to the insight that the factors which affect biting behaviour can be viewed as a hierarchy. The hierarchy extends from those that affect the onset of biting to those that affect its course.     

Food discrimination and induction of preference for artificial diets in the tobacco hornworm, Manduca sexta

ABSTRACT. Feeding discrimination of Manduca larvae reared on leaves and a variety of artificial media was tested against leaves, various media, solvent fractions of leaves and media, and media components, including pure chemicals. Field-collected animals showed the same preferences as did animals cultured in the laboratory for many generations. Rearing larvae on a leaf species, an artificial diet, or homogenized leaves added to artificial diet induced a preference for that food in subsequent choice tests. Extracts of these foods using organic solvents (particularly hexane) elicited feeding choices resembling those evoked by the foods themselves: water extracts were effective as stimulants or deterrents, but responses to them differed considerably from responses to the foods. Animals raised on a defined artificial diet showed an increased preference (or decreased deterrence) for the lipid component (linolenic acid) of that diet in behavioural tests. Thus induction of preference was shown to be influenced by a specific nutrient compound. Fifteen artificial diets were tested; three were successful, including a completely defined medium. Various components of the diets were tested for feeding preferences, both as omissions from the main diet and as pure compounds. Some were stimulatory, most were neutral or slightly deterrent; a few were strongly deterrent. With the exception of linolenic acid, preferences for pure compounds were not significantly correlated with the food on which the animals were reared. The data suggest that food discrimination depends on the perception of a complex chemical message comprised of both polar and non-polar compounds, with the latter being of somewhat greater importance. The results are consistent with the explanation of the induction of feeding preferences being due to a reduced responsiveness to deterrents, to an increased preference for feeding stimulants or to both.     

Olfactory responses to milkweed seed extracts in the milkweed bug

Electrophysiological studies showed that milkweed seed extracts have compounds which are stimulating to the olfactory chemoreceptors of the adult milkweed bug, Oncopeltus fasciatus. Ethanol extracts were the most stimulatory. These compounds may function as feeding attractants or stimulants. Sex, starvation, and mating did not affect the olfactory chemoreceptor responses.     

Potencies of combined doses of nucleotides as gorging stimulants for Rhodnius prolixus

The four nucleotides ATP, UTP, deoxyATP, and A(TETRA)P (adenosine tetraphosphate) were tested singly and in combinations for their potency in eliciting the gorging response of Rhodnius prolixus. All mixtures of ATP and dATP, and ATP and UTP, were more potent by a factor of 1.25 to 1.9 than predicted from their potencies when tested singly. No significant synergism or inhibition was seen with combinations of UTP and dATP, or ATP and A(TETRA)P. Lack of competitive inhibition suggests that physical fit between stimulating molecule and chemoreceptive protein rather than enzymatic modification of the stimulant is the mechanism of chemoreception of these compounds. The slight synergism seen is explained by competitive inhibition of a salivary ATPase.     

数种蜱类哈氏器感器的电生理反应

本实验用电生理方法研究了中华革蜱(Dermacentor sinicus)、森林革蜱(Derraacentor silvarum),和日本血蜱(Haemaphysalis japonica)成虫对不同化学刺激物(氨、冰醋酸、二氧化碳)和性信息素的成分(2,6-二氯酚、对-甲酚、苯酚和水杨醛),以及对温度变化和机械刺激的反应.从哈氏器感觉毛基部记录到的神经传人冲动用信号处理机进行脉冲密度分析,结果表明:(1)哈氏器上不同部位的感觉毛对各种刺激的敏感性不同;(2)蜱的嗅觉反应神经传入冲动有连续性和间歇性两种类型,并且有慢适宜的特点;(3)性信息素的成分中,2,6-二氯酚刺激引起的反应最强,是它的主要成分;(4)在一定浓度范围内,随着刺激物浓度加大反应增强;(5)吸血五天以后的雄蜱对氨的反应减弱,而对2,6-二氨酚的反成增强,吸血七天后反应最强;(6)两种革蜱对各种刺激反应的区别不大.     

Effect of plasma components on the feeding response of the mosquito Aedes aegypti L. to adenine nucleotides

ABSTRACT. The gorging response of Aedes aegypti to the ATP dissolved in platelet-poor plasma is greater than that of ATP dissolved in 0.15 m NaCl. The plasma components NaHCO₃ and albumin account for the full effect of the potentiation. Phosphate or tris buffers do not duplicate the bicarbonate effect. In 0.15 m NaCl with bicarbonate but lacking albumin the concentrations inducing 50% feeding are 58 μM ATP, 140 μM ADP, 460 μM AMP and 1500 μM cAMP. Non-adenine nucleotides such as ITP and GTP and phytic acid, and 2,3-diphosphoglyceric acid had no activity.     

Feeding response of Aphis pomi,Myzus persicae, and Amphorophora agathonica to phlorizin

Phlorizin, a phenolic compound present only in the apple genus, Malus, was found to be neutral as a probing stimulus to Aphis pomi, an apple feeder, but was a probing deterrent to the non-apple feeding aphids, Myzus persicae and Amphorophora agathonica. Phlorizin was an ingestion deterrent to all three species although the threshold was lower for A. pomi. Apple can be utilized as a host by A. pomi since it feeds in the phloem which appears not to contain phlorizin.     

Role of Blood Platelets in Haematophagy

RED blood corpuscles (RBC) suspended in saline induce gorging in many haematophagous insects because of their high intrinsic concentration of adenine nucleotides (ANS)^1–6. ANS are bound firmly inside the intact RBC, which raises the question of how they gain egress to contact the chemoreceptor surfaces and induce feeding. It has been suggested that saliva or secretions of the chemoreceptor surfaces act as ANS releasing agents¹. ANS release by haemolysis is discounted by the fact that all RBC found in the gut immediately after feeding are intact. Further, stereoscan electron microscopy of tsetse fly gustatory sensilla does not suggest that they operate by piercing the erythrocytes^7,8. Thus we decided to test the possibility that the chemoreceptors involved in blood identification receive an ANS stimulus from a source associated with, but not within the RBC.     

食物因素对笼养褐马鸡冬季打斗行为的影响

绝大多数动物社群中都存在着等级行为[2 ,10 ] ,高等级个体在取食、交配等方面都拥有优先权 ,最终导致高等级个体具有更高的存活率和繁殖率[1,3 ,4 ,7～ 9] 。这种等级行为可以避免频繁的打斗所带来的伤害和能量消耗。但是当争夺的资源很重要时 ,低等级个体将会忍受一定程度的代价以打斗的方式去争夺资源[6] 。有关食物分布格局和饥饿状况对鸟类取食打斗行为的影响几乎还为未见报道 ,本文利用冬季集群期内的一个笼养褐马鸡(Ｃｒｏｓｓｏｐｔｉｌｏｎｍａｎｔｃｈｕｒｉｃｕｍ )人工种群 ,研究了不同食物分布格局和饥饿状况下取食和打斗行为…     

Feeding responses of an oligophagous bean aphid, Megoura crassicauda, to primary and secondary substances in Vicia angustifolia

The feeding behaviour of the aphid Megoura crassicauda Mordivilko (Homoptera: Aphididae), which feeds selectively on plants in the genus Vicia (Fabaceae), was studied. The aphids deposited proteinaceous stylet sheaths intercellularly towards the phloem tissues of host plants. Similar stylet sheaths were formed on a Parafilm membrane when host‐specific acylated flavonoid glycosides [two 2″‐O‐(E)‐p‐coumaroyl esters of quercetin 3‐O‐diglycosides] present in the extracts of the narrow vetch, Vicia angustifolia L., were supplied in the solution covered by the membrane. In contrast, their corresponding deacyl analogues, present more abundantly in the host plant tissues, were not stimulatory, which suggested specificity in the structural requirements of the probing stimulants. While the aphids imbibed an artificial diet composed of primary nutrients (e.g., sucrose and amino acids) and produced a large quantity of honeydew, acylated flavonoids alone and non‐acylated flavonoids supplied with the nutrients more or less suppressed honeydew production. These findings implied that the acylated flavonoids serve as a cue to navigate the stylet sheath towards the phloem prior to sap‐sucking, whereas non‐acylated flavonoids may serve as a negative stimulus to refrain from sucking during tissue penetration before tapping the phloem, although the distribution of these compounds in the plant tissues remains unknown. Thus, the feeding behaviour of M. crassicauda appears to be controlled by multiple chemical stimuli in the process of the settling on its host plant.     

Evaluation of crystalline amino acids,betaine and AMP as food attractants of the giant tiger prawn (Penaeus monodon)

Laboratory observations of substrate probing by the chelate walking legs (chelipeds), antennular flicking rate and maxilliped activity of the prawn Penaeus monodon were used to evaluate various chemicals at seven different concentrations between 10⁻¹M and 10⁻⁷M as feeding stimulants. Exposure to amino acids (alanine, arginine, glutamine, glycine, isoleucine, serine and taurine) and betaine resulted in higher rates of substrate probing, antennular flicking and maxilliped activity in P. monodon at higher pipette concentrations (>10⁻²M) than at lower concentrations. Least response occurred in prawns which were exposed to nucleotide, adenosine 5′-monophosphate. Glutamine, betaine and taurine were the most effective single compounds tested, and stimulated significantly higher activities (p < 0.05) in prawns at concentrations above 10⁻⁶M than did controls (seawater only).An equimolar mixture of amino acids and betaine was also found to be an effective stimulant to P. monodon at concentrations above 10⁻⁶M and continued to elicit search responses in prawns at concentrations lower than that of any of the single chemicals. Such a strong response is consistent with synergistic interactions of the mixtures. All four molt stages tested (C, D₀, D₁, D₂) were equally responsive to food attractants.