POLYETHISM IN FORAGING IN A POLYMORPHIC PREDATOR, ENOPLOGNATHA OVATA (ARANEAE: THERIDIIDAE): A CASE FOR BALANCE

1999 ◽  
Vol 131 (2) ◽  
pp. 259-268 ◽  
Author(s):  
Carlos F. Greco ◽  
Peter G. Kevan
Keyword(s):  
Natural Population ◽  
Foraging Strategies ◽  
Strong Tendency ◽  
Balanced Polymorphism ◽  
Hunting Strategies ◽  
Misumena Vatia ◽  
Colour Morphs ◽  
Crab Spider ◽  
Artificial Flowers ◽  
Selection Of

AbstractTwo colour morphs of Enoplognatha ovata (Clerck), “redimita” and “lineata” the abdomens of which are whitish with two pink stripes and greyish-yellow, respectively, differ in their foraging strategies. When placed in artificial arenas with flowering stems to ascend, we noted that both morphs had a strong tendency to wander over the ground rather than ascend a stem [unlike the crab spider, Misumena vatia Clerck (Araneae: Thomisidae)], but that lineata was significantly more prone to wander than was redimita. Neither morph showed choice for the type of stem or colour of flower. Nevertheless, redimita showed a greater preference for choosing white artificial flowers (discs) atop 30-cm wooden rods than did lineata. We propose that the relative abundances of the two colour morphs in the natural population represents a balanced polymorphism which is maintained in part by polyethism in hunting strategies, with redimita being more fastidious in its selection of cryptic hunting sites in flowers than is lineata, and the latter being more cryptic and more errant on the ground.

Contrasting patch choosing by anthophilous ambush predators: vegetation and floral cues for decisions by a crab spider (Misumena vatia) and males and females of an ambush bug (Phymata americana)

1994 ◽  
Vol 72 (9) ◽  
pp. 1583-1588 ◽  
Author(s):  
Carlos F. Greco ◽  
Peter G. Kevan
Keyword(s):  
Cirsium Arvense ◽  
Patch Selection ◽  
Significant Preference ◽  
Patch Choice ◽  
Clear Preference ◽  
Misumena Vatia ◽  
Males And Females ◽  
Crab Spider ◽  
Artificial Flowers ◽  
Ambush Predators

Field-collected individuals of Misumena vatia and Phymata americana were compared experimentally as to the kind of vegetation and flower cues they use to choose a hunting site, by introducing them into choice arenas with variously manipulated natural stems of three species of plant and with artificial flowers. Misumena vatia showed a strong preference for stems with flowers or leaves or both; P. americana did not prefer normal stems as strongly and it did not show a statistically significant preference among the various manipulated patches. Both predators discriminated among Solidago canadensis, Daucus carota, and Cirsium arvense, showing a clear preference for the first. Misumena vatia showed a clear preference for yellow artificial flowers on wooden sticks when given a choice of four different colours. Phymata americana preferred yellow or blue to white or red, showing no discrimination between colours of the same group (yellow vs. blue or white vs. red). Misumena vatia took the longest time (ca. 43 min) to complete its choice of stem; female and male P. americana took 18 and 15 min, respectively. In all the experiments P. americana showed sexual diethism, the females being more choosy than the males. The ranking of discrimination from greatest to least was as follows: M. vatia, females of P. americana, and males of P. americana. We suggest that both species of predators have different strategies of patch choice and that in the case of P. americana, males and females have different patterns of patch selection, the males searching not only for prey but also for mates.

scholarly journals AN ATTEMPT TO ESTIMATE TEAT QUALITY OF SOWS BY HAND MILKING DURING FARROWING

1984 ◽  
Vol 64 (1) ◽  
pp. 165-170 ◽  
Author(s):  
D. FRASER ◽  
C. S. LIN
Keyword(s):  
Key Words ◽  
Strong Tendency ◽  
Teat Number ◽  
Selection Of

For 21 sows, teats were hand milked individually in a standard way during farrowing in an attempt to produce an index of teat quality. The piglets' teat selection and 14-day weights were then compared with the hand milking results. Of within-litter variation in 14-day weight, 38.6% was explained by 1-day weight, and only 4.6% extra variation by the index derived from hand milking. Use of the index gave no improvement over previous models involving 1-day weight and teat number (anterior to posterior). Hand milking showed a pronounced decline in colostrum yield from the most anterior teat pair (46.8 g) to the most posterior (13.7 g); this may help to explain the piglets' strong tendency to select anterior positions. Piglets of high, medium and low 1-day weight differed significantly in liveweight gain, but not in their selection of anterior or posterior teats. Key words: Colostrum, milk, piglet, sow, suckling behavior, teat quality

Long- versus short-range foraging strategies of hoary (Lasiurus cinereus) and silver-haired (Lasionycteris noctivagans) bats and the consequences for prey selection

1985 ◽  
Vol 63 (11) ◽  
pp. 2507-2515 ◽  
Author(s):  
Robert M. R. Barclay
Keyword(s):  
Short Range ◽  
Prey Availability ◽  
Prey Selection ◽  
Foraging Strategy ◽  
Foraging Strategies ◽  
Lasiurus Cinereus ◽  
Echolocation Calls ◽  
Straight Line ◽  
Lasionycteris Noctivagans ◽  
Selection Of

Habitat use, temporal activity, foraging behaviour, and prey selection of hoary bats (Lasiurus cinereus) and silver-haired bats (Lasionycteris noctivagans) were studied at Delta Marsh, Manitoba. Bat activity was assessed by monitoring echolocation calls with ultrasonic detectors. Prey availability was determined using sticky and Malaise traps and dietary information was obtained from fecal analysis. Both species were active all night and foraged primarily in the lee of a narrow forested ridge. Lasionycteris noctivagans foraged in a manner that indicates that it detects and pursues prey over short distances. These bats fly slowly, are highly manoeuverable, and were commonly observed feeding on swarms of insects in small clearings. They use echolocation calls that support the notion of a short-range foraging strategy and feed opportunistically on whatever insects are available. Lasiurus cinereus, on the other hand, uses a long-range prey detection and pursuit foraging strategy. They fly rapidly along straight line paths in open areas and use echolocation calls designed to detect insects at a distance. The diet consists primarily of large insects (moths, beetles, and dragonflies), but the bats nonetheless feed opportunistically. The foraging strategy likely restricts the availability and profitability of small insects as prey.

Resistance of glucose-6-phosphate dehydrogenase deficiency to malaria: effects of fava bean hydroxypyrimidine glucosides onPlasmodium falciparumgrowth in culture and on the phagocytosis of infected cells

Parasitology ◽  
1996 ◽  
Vol 113 (1) ◽  
pp. 7-18 ◽  
Author(s):  
H. Ginsburg ◽  
H. Atamna ◽  
G. Shalmiev ◽  
J. Kanaani ◽  
M. Krugliak
Keyword(s):  
Dehydrogenase Deficiency ◽  
Dietary Habits ◽  
Phagocytic Cells ◽  
Balanced Polymorphism ◽  
Fava Bean ◽  
Infected Cells ◽  
Fava Beans ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Hydrolysis Of ◽  
Selection Of

SUMMARYThe balanced polymorphism of glucose-6-phosphate dehydrogenase deficiency (G6PD-) is believed to have evolved through the selective pressure of malaria combined with consumption of fava beans. The implicated fava bean constituents are the hydroxypyrimidine glucosides vicine and convicine, which upon hydrolysis of their β-O-glucosidic bond, become potent pro-oxidants. In this work we show that the glucosides inhibit the growth ofPlasmodium falciparum, increase the hexose-monophosphate shunt activity and the phagocytosis of malaria-infected erythrocytes. These activities are exacerbated in the presence of β-glucosidase, implicating their pro-oxidant aglycones in the toxic effect, and are more pronounced in infected G6PD-erythrocytes. These results suggest that G6PD-infected erythrocytes are more susceptible to phagocytic cells, and that fava bean pro-oxidants are more efficiently suppressing parasite propagation in G6PD-erythrocytes, either by directly affecting parasite growth, or by means of enhanced phagocytic elimination of infected cells. The present findings could account for the relative resistance of G6PD-bearers to falciparum malaria, and establish a link between dietary habits and malaria in the selection of the G6PD-genotype.

scholarly journals Phytochemical cues affect hunting-site choices of a nursery web spider (Pisaura mirabilis) but not a crab spider (Misumena vatia)

2011 ◽  
Vol 39 (1) ◽  
pp. 113-117 ◽  
Author(s):  
Robert R. Junker ◽  
Simon Bretscher ◽  
Stefan Dötterl ◽  
Nico Blüthgen
Keyword(s):  
Web Spider ◽  
Misumena Vatia ◽  
Crab Spider ◽  
Pisaura Mirabilis

scholarly journals Comparative analysis on visual and olfactory signals of Papilio xuthus (Lepidoptera: Papilionidae) during foraging and courtship

2020 ◽  
Author(s):  
Jie Liu ◽  
Mingtao Li ◽  
Shunan Chen ◽  
Lei Shi ◽  
Xiaoming Chen
Keyword(s):  
Comparative Analysis ◽  
Natural Population ◽  
Organic Chemicals ◽  
Olfactory Perception ◽  
Olfactory Responses ◽  
Papilio Xuthus ◽  
Volatile Organic ◽  
Volatile Organic Chemicals ◽  
Artificial Flowers

Abstract In this study, we examined the roles of visual and olfactory responses during foraging and courtship of the butterfly Papilio xuthus. Our results showed that P. xuthus was sensitive to color in the range of 350–500 nm. Visits of P. xuthus females and males to blue, purple, and red artificial cloth flowers were ♀ 54.90% and ♂ 39.22%, ♀ 19.61% and ♂ 35.29%, and ♀ 9.80% and ♂ 19.61%, respectively. Application of 10% honey on these artificial flowers resulted in an increase of 3.41 and 3.26 fold in flower visits by the butterfly in comparison with controls. When 10% honey water was sprayed on colorless artificial flowers, flower visits reduced seven fold for females and two fold for males, indicating that both visual and olfactory perceptions play important roles during foraging. During courtship, four types of chasing were observed in a natural population of P. Xuthus. The four types are males chasing females (49%), males chasing males (25%), females chasing males (13%), and females chasing females (10%). However, when odorless artificial mimics of butterflies were used, no significant differences were observed among these types of chasing, indicating that olfactory perception was crucial for the butterfly during courtship. Profiling volatile organic chemicals and individual bioassays revealed that α-farnesene might play an important role in distinguishing males from females during courtship of the butterfly.

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