Host finding behaviour as a predictor of foraging strategy in entomopathogenic nematodes

Parasitology ◽  
1994 ◽  
Vol 108 (2) ◽  
pp. 207-215 ◽  
Author(s):  
P. S. Grewal ◽  
E. E. Lewis ◽  
R. Gaugler ◽  
J. F. Campbell
Keyword(s):  
Filter Paper ◽  
Entomopathogenic Nematodes ◽  
Foraging Strategy ◽  
Host Finding ◽  
Steinernema Feltiae ◽  
Foraging Strategies ◽  
Directional Response ◽  
Sand Column ◽  
Steinernema Glaseri ◽  
Volatile Cues

SUMMARYForaging strategies of eight species of entomopathogenic nematodes were predicted from their response to host volatile cues and dispersal behaviour on 2-dimensional substrates. Positive directional response to chemical cues and similar distances travelled on smooth (agar) or nictation substrates (agar overlaid with sand grains) by Heterorhabditis bacterio-phora, Heterorhabditis megidis, Steinernema anomali, and Steinernema glaseri suggest their cruising approach to finding hosts. The absence of directional response and less distance travelled on nictation substrate, than on smooth agar by Steinernema carpocapsae and Steinernema scapterisci suggest their ambushing mode of foraging. Steinernema feltiae and Steinernema sp. responded directionally to host volatiles, but travelled less distance on the nictation substrate than on smooth agar; the two species also did not nictate. The cruiser species located hosts more effectively in the sand columns, whereas the ambushers were more effective at finding hosts on filter paper. Steinernema feltiae and Steinernema sp. performed equally on filter paper and in the sand column. We conclude that H. bacteriophora, H. megidis, S. anomali and S. glaseri cruise to find hosts, whereas S. carpocapsae and S. scapterisci ambush hosts. Steinernema feltiae and Steinernema sp. are intermediary in the search continuum sharing some characteristics of both ambush and cruise foragers.

Hierarchical order of host cues in parasite foraging strategies

Parasitology ◽  
1995 ◽  
Vol 110 (2) ◽  
pp. 207-213 ◽  
Author(s):  
E. E. Lewis ◽  
P. S. Grewal ◽  
R. Gaugler
Keyword(s):  
Steinernema Carpocapsae ◽  
Steinernema Feltiae ◽  
Foraging Strategies ◽  
Natural Order ◽  
Steinernema Glaseri ◽  
Host Materials ◽  
Contextual Framework ◽  
In Series ◽  
Volatile Cues ◽  
Host Cues

SUMMARYThe importance of host cues to three species of steinernematid nematodes (Rhabdita: Steinernematidae) with different foraging strategies was compared. We presented host materials to nematodes in series to test responses to combinations of host cues. If a fixed hierarchy of cues is followed during foraging, parasites should respond most strongly to cues offered in natural order. Steinernema carpocapsae, an ambush forager, aggregated at the source of volatile host cues only after attachment to host cuticle. They also parasitized hosts more efficiently after contact with cuticle. Steinernema glaseri, a cruise forager, was unaffected by exposure to combinations of host cues. Steinernema feltiae, a nematode with characteristics of both ambushing and cruising, was affected by cue hierarchies when either contact or volatile cues were presented first. Host-associated materials encountered out of the context may not qualify as host cues for the ambush forager, S. carpocapsae. Perhaps the order in which cues are encountered is more predictable for ambushers than for cruisers. Therefore an ambusher's response to host materials has a more fixed contextual framework.

Entomopathogenic nematode host finding: response to host contact cues by cruise and ambush foragers

Parasitology ◽  
1992 ◽  
Vol 105 (2) ◽  
pp. 309-315 ◽  
Author(s):  
E.E. Lewis ◽  
R. Gaugler ◽  
R. Harrison
Keyword(s):  
Entomopathogenic Nematode ◽  
Nematode Species ◽  
Host Finding ◽  
Steinernema Carpocapsae ◽  
Foraging Strategies ◽  
Popillia Japonica ◽  
Search Behaviour ◽  
Search Area ◽  
Steinernema Glaseri ◽  
Host Cues

SUMMARYSearch behaviour of two entomopathogenic nematode species with different foraging strategies was compared by measuring parameters of unrewarded search after contact with host cues. Steinernema glaseri cruises in search of hosts. Steinernema carpocapsae ambushes hosts. Nematodes should respond to contact with relevant host cues by shifting their search from ranging to localized after contact with them. We predicted that cruising foragers rely on chemical cues more heavily than ambushers. These species were also tested for host affinities. Nematodes were tracked by image analysis after exposure to faeces, cuticle or food of either Popillia japonica or Spodoptera exiqua. Steinernema glaseri responded to selected host cues by shifting from ranging to localized search, characterized by decreased locomotory rate, distance travelled, search area and the proportion of the test period spent moving. Steinernema carpocapsae did not respond to host cues. Steinernema glaseri responds to selected chemical host cues for host location, whereas S. carpocapsae does not.

Scavenging or infection? Possible host choosing by entomopathogenic nematodes

Nematology ◽  
2008 ◽  
Vol 10 (2) ◽  
pp. 251-259 ◽  
Author(s):  
Ernesto San-Blas ◽  
Barbara Pembroke ◽  
Simon Gowen
Keyword(s):  
Entomopathogenic Nematodes ◽  
Galleria Mellonella ◽  
Nematode Species ◽  
Foraging Strategy ◽  
Steinernema Feltiae ◽  
Natural Field ◽  
Heterorhabditis Megidis ◽  
The Dead

AbstractEntomopathogenic nematodes are able to survive by scavenging. We tested Steinernema feltiae, S. affine and Heterorhabditis megidis alone or in different combinations to evaluate the responses of these nematodes when dead or live Galleria mellonella larvae were offered. Steinernema feltiae and S. affine scavenged upon dead G. mellonella larvae and about 30% more dead larvae were penetrated than live ones. By contrast, H. megidis penetrated more live larvae than dead ones. When the nematode species were combined, the results varied among the combinations, but the dead larvae were always used as a host. The behaviour of natural field populations of S. feltiae and S. affine was also compared. Steinernema feltiae showed no difference between scavenging and performing 'normal infections', whereas S. affine scavenged to a reduced amount (around 60% less); this difference could be related to the particular foraging strategy of these nematodes.

Changes in foraging behaviour during the infective stage of entomopathogenic nematodes

Parasitology ◽  
1995 ◽  
Vol 110 (5) ◽  
pp. 583-590 ◽  
Author(s):  
E. E. Lewis ◽  
S. Selvan ◽  
J. F. Campbell ◽  
R. Gaugler
Keyword(s):  
Metabolic Rate ◽  
Entomopathogenic Nematodes ◽  
Storage Period ◽  
Foraging Strategy ◽  
Heterorhabditis Bacteriophora ◽  
Steinernema Carpocapsae ◽  
Foraging Strategies ◽  
Infective Juvenile ◽  
Infective Stage ◽  
Energy Reserves

SUMMARYStudies of foraging strategies are often complicated by competing goals of the forager. In contrast, non-feeding infective juvenile entomopathogenic nematodes forage exclusively for a single host. Two questions were posed: (1) what is the relationship between metabolic rate, energy reserves and foraging strategy and (2) when a foraging strategy fails, will an infective-stage parasite switch strategies? Three species of entomopathogenic nematodes were stored in water and changes in their behaviour, metabolic rate, energy reserves, and infectivity were measured throughout the storage period. Steinernema carpocapsae ambushes insect hosts, whereas S. glaseri and Heterorhabditis bacteriophora cruise forage. Steinernema carpocapsae was least active and had the lowest metabolic rate. Heterorhabditis bacteriophora was more active and had the highest metabolic rate. Steinernema glaseri was most active and had an intermediate metabolic rate. Neither cruising species changed foraging strategy. Steinernema carpocapsae decreased nictation (a behaviour associated with ambushing only) and increased their locomotory rate. Any change in searching strategy occurred without assessment of the profitability or distribution of potential hosts, but the advantage this confers is unknown.

scholarly journals Chemical Cues from Entomopathogenic Nematodes Vary Across Three Species with Different Foraging Strategies, Triggering Different Behavioral Responses in Prey and Competitors

2021 ◽  
Author(s):  
John M. Grunseich ◽  
Natalie M. Aguirre ◽  
Morgan N. Thompson ◽  
Jared G. Ali ◽  
Anjel M. Helms
Keyword(s):  
Entomopathogenic Nematodes ◽  
Chemical Cues ◽  
Prey Availability ◽  
Foraging Strategy ◽  
Foraging Strategies ◽  
Predator Species ◽  
Hunting Strategies ◽  
Prey Behavior ◽  
Cucumber Beetle ◽  
Predator Foraging

AbstractChemical cues play important roles in predator–prey interactions. Semiochemicals can aid predator foraging and alert prey organisms to the presence of predators. Previous work suggests that predator traits differentially influence prey behavior, however, empirical data on how prey organisms respond to chemical cues from predator species with different hunting strategies, and how foraging predators react to cues from potential competitors, is lacking. Furthermore, most research in this area has focused on aquatic and aboveground terrestrial systems, while interactions among belowground, soiling-dwelling organisms have received relatively little attention. Here, we assessed how chemical cues from three species of entomopathogenic nematodes (EPNs), each with a different foraging strategy, influenced herbivore (cucumber beetle) and natural enemy (EPN) foraging behavior. We predicted these cues could serve as chemical indicators of increased predation risk, prey availability, or competition. Our findings revealed that foraging cucumber beetle larvae avoided chemical cues from Heterorhabditis bacteriophora (active-foraging cruiser EPNs), but not Steinernema carpocapsae (ambusher EPNs) or Steinernema riobrave (intermediate-foraging EPNs). In contrast, foraging H. bacteriophora EPNs were attracted to cues produced by the two Steinernema species but not conspecific cues. Notably, the three EPN species produced distinct blends of olfactory cues, with only a few semi-conserved compounds across species. These results indicate that a belowground insect herbivore responds differently to chemical cues from different EPN species, with some EPN species avoiding prey detection. Moreover, the active-hunting EPNs were attracted to heterospecific cues, suggesting these cues indicate a greater probability of available prey, rather than strong interspecific competition.

scholarly journals The influence of habitat quality on the foraging strategies of the entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis megidis

Parasitology ◽  
2009 ◽  
Vol 137 (2) ◽  
pp. 303-309 ◽  
Author(s):  
L. M. KRUITBOS ◽  
S. HERITAGE ◽  
S. HAPCA ◽  
M. J. WILSON
Keyword(s):  
Habitat Quality ◽  
Entomopathogenic Nematodes ◽  
Natural Habitat ◽  
Host Finding ◽  
Steinernema Carpocapsae ◽  
Foraging Strategies ◽  
Heterorhabditis Megidis ◽  
Soil Media ◽  
Contrasting Habitats ◽  
Outdoor Mesocosms

SUMMARYEntomopathogenic nematodes (EPN) are soil-transmitted parasites and their foraging strategies are believed to range from ‘ambush’ to ‘cruise’ foragers. However, research on their behaviour has not considered the natural habitat of these nematodes. We hypothesized that EPN behaviour would be influenced by soil habitat quality and tested this hypothesis using 2 EPN species Steinernema carpocapsae (an ‘ambusher’) and Heterorhabditis megidis (a ‘cruiser’) in 2 contrasting habitats, sand and peat. As predicted from previous studies, in sand most S. carpocapsae remained at the point of application and showed no taxis towards hosts, but in peat S. carpocapsae dispersed much more and showed a highly significant taxis towards hosts. H. megidis dispersed well in both media, but only showed taxis towards hosts in sand. In outdoor mesocosms in which both species were applied, S. carpocapsae outcompeted H. megidis in terms of host finding in peat, whereas the opposite was true in sand. Our data suggest that these 2 EPN may be habitat specialists and highlight the difficulties of studying soil-transmitted parasites in non-soil media.

scholarly journals Reproduction of entomopathogenic nematodes (Steinernema feltiae) on different insect hosts under laboratory conditions

2019 ◽  
pp. 161-174
Author(s):  
D. Sigareva ◽  
V. Kharchenko
Keyword(s):  
Filter Paper ◽  
Entomopathogenic Nematodes ◽  
Steinernema Feltiae ◽  
Insect Host ◽  
Sterile Soil ◽  
Infective Larvae ◽  
Laboratory Conditions ◽  
The Common ◽  
Petri Dishes ◽  
Wax Moth

Goal. To identify the effectiveness of entomopathogenic nematodes (Steinernema feltiae isolate with a biological product «Entonem» ™ Copert) on the larvae and adults of different insect pests at various ways of their infection, and to explore the possibility of generating a significant amount of the invasive larvae of entomopathogenic nematodes (EPN). Research methods. The material for our study is the 7 types of test insects: larvae of the large and the small wax moth, castaneum flour, gyroscope, common cabbage butterfly, Kovalik pilosula, as well as the may beetle, which was used stage larvae, as well as individuals of adult beetles (imago). All the studied insects infected with EPN (pathogen — Steinernema feltiae with biopreparation «Entonem» (™Koppert)) in the laboratory on filter paper or in sterile soil. Recorded date of infection and death of insects and counted the number of allocated of each type of insect infective larvae of nematodes. Estimated duration of migration and reproductive potential of different test insects. Results. The use of different methods of infection (dry contact parasite and insect hosts on filter paper or by making a dose in sterile soil, which was placed insect-host) at a dose of 50 larvae per one insect, showed that in half of the cases a significant difference between them is not detected. However, castaneum flour, Kovalik pilosula and ordinary spinning top, the best was the method of contamination in the Petri dishes, and adults of the may beetle — in groundwater samples. The duration of the process of migration of larvae of the entomopathogenic nematodes from the cadavers of insect hosts ranged from 27—51 day and were more dependent on the insect host than from its method of infection. A short period of migration of the larvae of large and small wax moth (27—36 days), long (35—45) from larvae of a top common and castaneum flour, the longest period of time (48—51 hours) — larvae of cabbage butterflies and a beetle may. Performance in relation to the amount of the newly formed infective larvae determines the insect host. Among the investigated 7-insects-the home of highest performance was observed in the may beetle (115980—120060 larvae) and the cabbage (93440—97880 larvae). Less productive was the great wax moth, the flour castaneum and the grasshopper pelousy (respectively 26880 ± 420; 34500 ± 430; 32400 ± 673).Less productive are the common top, the May beetle (imago) and the small wax moth, in which from 15640 to 26880 invasive larvae were formed. Findings. In laboratory conditions, without significant material costs, you can get a sufficient number of entomopathogenic nematodes. The method of directly introducing entomopathogenic nematodes onto test insects in Petri dishes proved to be the best compared to soil invasion. The duration and volume of migration of larvae of entomopathogenic nematodes is determined mainly by the species of host insects. The shortest migration period was recorded in wax moth larvae (small and large), significantly longer (almost 1.5 times) in the larvae of May beetle and cabbage. The most productive in relation to juvenile larvae of EPN were the cabbage and the larvae of the May beetle, and the least productive ones were the common top, May beetle (imago) and small wax moth.

Response of cruiser and ambusher entomopathogenic nematodes (Steinernematidae) to host volatile cues

1993 ◽  
Vol 71 (4) ◽  
pp. 765-769 ◽  
Author(s):  
Edwin E. Lewis ◽  
Randy Gaugler ◽  
Robert Harrison
Keyword(s):  
Carbon Dioxide ◽  
Cuticular Hydrocarbons ◽  
Entomopathogenic Nematodes ◽  
Galleria Mellonella ◽  
Petri Dish ◽  
Nematode Species ◽  
Steinernema Carpocapsae ◽  
Assay Method ◽  
Steinernema Glaseri ◽  
Volatile Cues

Two species of entomopathogenic nematodes, an ambush forager (Steinernema carpocapsae) and a cruising forager (S. glaseri), were assayed for their responses to volatiles associated with Galleria mellonella (Insecta: Lepidoptera). The responses of entomopathogenic nematodes to six host-associated volatile treatments were assayed. Live G. mellonella, live G. mellonella with the cuticular hydrocarbons removed, live G. mellonella with carbon dioxide removed, dead G. mellonella, dead G. mellonella with the cuticular hydrocarbons removed, and volatiles from S. exiqua feces were assayed in a Y-tube choice aparatus. Steinernema glaseri were attracted only to treatments producing carbon dioxide. Steinernema carpocapsae showed no significant response to any treatments tested. To assess the directionality of the response toward live G. mellonella, net average movement per nematode after 5, 10, and 20 min was measured for both nematode species. The assay method was based on the "quadrant plate" bioassay, with a 9 cm Petri dish containing 2% agar. Steinernema carpocapsae showed little directionality of response, whereas S. glaseri was attracted to carbon dioxide. We conclude that carbon dioxide attracts S. glaseri to areas likely to hold hosts. Ambush foragers are less influenced by cues associated with hosts or their habitat.

scholarly journals Be different to be better: the effect of personality on optimal foraging with incomplete knowledge

2021 ◽  
Author(s):  
Poppy M. Jeffries ◽  
Samantha C. Patrick ◽  
Jonathan R. Potts
Keyword(s):  
Optimal Foraging ◽  
Optimal Foraging Theory ◽  
Foraging Strategy ◽  
Foraging Strategies ◽  
Partial Knowledge ◽  
Marginal Value ◽  
Animal Populations ◽  
Plausible Mechanism ◽  
Insight Into ◽  
Modelling Approach

AbstractMany animal populations include a diversity of personalities, and these personalities are often linked to foraging strategy. However, it is not always clear why populations should evolve to have this diversity. Indeed, optimal foraging theory typically seeks out a single optimal strategy for individuals in a population. So why do we, in fact, see a variety of strategies existing in a single population? Here, we aim to provide insight into this conundrum by modelling the particular case of foraging seabirds, that forage on patchy prey. These seabirds have only partial knowledge of their environment: they do not know exactly where the next patch will emerge, but they may have some understanding of which locations are more likely to lead to patch emergence than others. Many existing optimal foraging studies assume either complete knowledge (e.g. Marginal Value Theorem) or no knowledge (e.g. Lévy Flight Hypothesis), but here we construct a new modelling approach which incorporates partial knowledge. In our model, different foraging strategies are favoured by different birds along the bold-shy personality continuum, so we can assess the optimality of a personality type. We show that it is optimal to be shy (resp. bold) when living in a population of bold (resp. shy) birds. This observation gives a plausible mechanism behind the emergence of diverse personalities. We also show that environmental degradation is likely to favour shyer birds and cause a decrease in diversity of personality over time.

Allelopathy: a possible mechanism of suppression of plant-parasitic nematodes by entomopathogenic nematodes

Nematology ◽  
1999 ◽  
Vol 1 (7) ◽  
pp. 735-743 ◽  
Author(s):  
Parwinder S. Grewal ◽  
Edwin E. Lewis ◽  
Sudha Venkatachari
Keyword(s):  
Meloidogyne Incognita ◽  
Entomopathogenic Nematodes ◽  
Galleria Mellonella ◽  
Steinernema Feltiae ◽  
Symbiotic Bacteria ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Tomato Roots ◽  
Xenorhabdus Nematophilus ◽  
Plant Parasitic

Abstract A possible mechanism of suppression of a plant-parasitic nematode Meloidogyne incognita by entomopathogenic nematodes is described. Heat-killed entomopathogenic nematodes Steinernema feltiae and S. riobrave temporarily suppressed penetration of the root-knot nematode M. incognita into tomato roots, but live nematodes had no effect. Infective juvenile M. incognita were repelled from all entomopathogenic nematode treatments that included their symbiotic bacteria. They were repelled by Galleria mellonella cadavers infected with S. carpocapsae, S. feltiae, and S. riobrave and from cell-free culture filtrates of the symbiotic bacteria Xenorhabdus nematophilus, X. bovienii, and Xenorhabdus sp. "R" from the three nematode species, respectively. Cell-free filtrates from all three Xenorhabdus spp. were toxic to M. incognita infective juveniles causing 98-100% mortality at 15% concentration. Cell-free filtrate of Xenorhabdus sp. "R" also reduced the hatch of M. incognita eggs. Application of formulated bacterial cell-free filtrates temporarily suppressed M. incognita penetration into tomato roots in a greenhouse trial. The short-term effects of cell-free bacterial filtrates, namely toxicity and repellency, were almost entirely due to ammonium. These results demonstrate allelopathic interactions between plant-parasitic nematodes, entomopathogenic nematodes and their symbiotic bacteria. The likely role of allelopathy in the suppression of plant-parasitic nematodes by innundative applications of entomopathogenic nematodes is discussed. Allelopathie: Ein moglicher Mechanismus zur Unterdruckung pflanzenparasitarer Nematoden durch insektenpathogene Nematoden - Es wird ein moglicher Mechanismus zur Unterdruckung des pflanzenparasitaren Nematoden Meloidogyne incognita durch insektenpathogene Nematoden beschrieben. Durch Hitze abgetotete insektenpathogene Nematoden Steinernema feltiae und S. riobrave underdruckten das Eindringen des Wurzelgallenalchens M. incognita in Tomatenwurzeln, lebende Nematoden hatten keine Wirkung. Infektionsjuvenile von M. incognita wurden von allen Behandlungen mit insektenpathogenen Nematoden abgestossen, die auch die symbiontischen Bakterien einschlossen. Sie wurden durch die Kadaver von Galleria mellonella abgestossen, die mit S. carpocapsae, S. feltiae und S. riobrave infiziert waren sowie durch zellfreie Kultursubstrate der symbiontischen Bakterien Xenorhabdus nematophilus, X. bovienii und Xenorhabdus sp. "R" aus den drei genannten Nematodenarten. Zellfreie Kultursubstrate von allen drei Xenorhabdus spp. waren giftig fur die Infektionsjuvenilen von M. incognita und verursachten in einer Konzentration von 15% Abtotungsraten von 98-100%. Zellfreie Kultursubstrate von Xenorhabdus sp. "R" vermiderten ausserdem das Schlupfen von M. incognita-Eiern. In einem Gewachshausversuch unterdruckten formulierte zellfreie Bakterienfiltrate vorubergehend das Eindringen von M. incognita in Tomatenwurzeln. Die Kurzzeitwirkungen von zellfreien Bakterien filtraten, namentlich Giftigkeit und Abstossung, waren nahezu ganz bedingt durch Ammoniak. Diese Ergebnisse zeigen das Vorhandensein von allelopathischen Wechselwirkungen zwischen pflanzenparasitaren Nematoden, insektenpathogenen Nematoden und deren symbiontischen Bakterien. Die wahrscheinliche Rolle von Allelopathie bei der Unterdruckung pflanzenparasitarer Nematoden durch eine Massenanwendung insektenpathogener Nematoden wird diskutiert.

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