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

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.

1998 ◽  
Vol 33 (1) ◽  
pp. 40-48 ◽  
Author(s):  
Monica L. Townsend ◽  
Donn T. Johnson ◽  
Don C. Steinkraus

In the laboratory, four nematode species differed significantly in the percentage mortality that each caused in second-instar green June beetles (grubs), Cotinis nitida (L.). Water suspensions of 1,000 infective juveniles (IJ)/one grub/Petri dish each of Heterorhabditis bacteriophora, Steinernema glaseri, and S. feltiae caused 34, 22 and 18% grub mortality, respectively. These values were significantly (P = 0.05) greater than the grub mortality caused by either S. carpocapsae (12%) or the water check (0%) that were similar. Several factors affected third- and fourth-instar susceptibility in the laboratory when exposed to 10,000 S. carpocapsae or H. bacteriophora IJ in 75 g of soil (133 IJ/cm3 soil)/plastic cup. Soil at 30% moisture by weight resulted in significantly more (P= 0.006) dead grubs (6.6%) than at 10% soil moisture (2.8%). Significantly more (P = 0.03) grubs died when at a grub density of 2 grubs/plastic cup (5.6%) than at 1 grub/plastic cup (3.8%). Significantly more (P = 0.01) grubs were killed by either S. carpocapsae and H. bacteriophora at a soil temperature of 25°C (6.5%) than at 12°C (2.8%). There was also a significant interaction of temperature and nematode species. Heterorhabditis bacteriophora killed significantly more (P= 0.02) grubs at 25°C (9.5%) than at 12°C (1.9%) and more than S. carpocapsae killed at either 12°C or 25°C (<3.9%). More virulent nematode strains or species than these four nematode species must be identified if green June beetles are to be controlled by nematodes.


2016 ◽  
Vol 10 (1) ◽  
pp. 26 ◽  
Author(s):  
Yuliantoro Baliadi ◽  
E. Kondo ◽  
T. Yoshiga

The non-feeding developmentally arrested infective juveniles (IJs) of entomopathogenic nematodes in the family of Steinernematidae and Heterorhabditidae seek out a susceptible insect host and initiate infections. The aim of the research was to examine the continual<br />forming and contribution of IJs produced via endotokia matricida (IJs-EM) of Heterorhabditis bacteriophora, Steinernema glaseri, and S. carpocapsae. The research was conducted at the Laboratory of Nematology of the Saga University, Japan (April 2001-April<br />2002) and the Laboratory of Nematology of the Indonesian Legume and Tuber Crops Research Institute (June 2003-October 2004). The nematode progenies were investigated using the greater wax moth, Galleria mellonella, pre-inoculated with 50 IJs at 25°C.<br />Results showed that three reproductive adult generations were observed at day 18th. There were 135,000, 128,000 and 133,000 IJs per insect cadaver produced in H. bacteriophora, S. glaseri and S. carpocapsae, respectively. Endotokia matricida contributed a higher number of IJs than that of a normal mode of IJs production. The ratios are 81%, 28% and 64% for H. bacteriophora, S. glaseri, and S. carpocapsae of the IJs total production, respectively. Among the generations, the highest contribution of IJs was come from the<br />third adult generation bearing endotokia matricida, i.e., 63%, 24% and 51% for the three nematode species. Although the IJs-EM were more transparent compared to the normal IJs, they were morphologically similar. The results show that endotokia matricida has a pivotal role in a species maintenance and survival strategy of entomopathogenic nematodes in extreme environmental conditions.


2016 ◽  
Vol 10 (1) ◽  
pp. 26 ◽  
Author(s):  
Yuliantoro Baliadi ◽  
E. Kondo ◽  
T. Yoshiga

The non-feeding developmentally arrested infective juveniles (IJs) of entomopathogenic nematodes in the family of Steinernematidae and Heterorhabditidae seek out a susceptible insect host and initiate infections. The aim of the research was to examine the continual<br />forming and contribution of IJs produced via endotokia matricida (IJs-EM) of Heterorhabditis bacteriophora, Steinernema glaseri, and S. carpocapsae. The research was conducted at the Laboratory of Nematology of the Saga University, Japan (April 2001-April<br />2002) and the Laboratory of Nematology of the Indonesian Legume and Tuber Crops Research Institute (June 2003-October 2004). The nematode progenies were investigated using the greater wax moth, Galleria mellonella, pre-inoculated with 50 IJs at 25°C.<br />Results showed that three reproductive adult generations were observed at day 18th. There were 135,000, 128,000 and 133,000 IJs per insect cadaver produced in H. bacteriophora, S. glaseri and S. carpocapsae, respectively. Endotokia matricida contributed a higher number of IJs than that of a normal mode of IJs production. The ratios are 81%, 28% and 64% for H. bacteriophora, S. glaseri, and S. carpocapsae of the IJs total production, respectively. Among the generations, the highest contribution of IJs was come from the<br />third adult generation bearing endotokia matricida, i.e., 63%, 24% and 51% for the three nematode species. Although the IJs-EM were more transparent compared to the normal IJs, they were morphologically similar. The results show that endotokia matricida has a pivotal role in a species maintenance and survival strategy of entomopathogenic nematodes in extreme environmental conditions.


Parasitology ◽  
1992 ◽  
Vol 105 (2) ◽  
pp. 309-315 ◽  
Author(s):  
E.E. Lewis ◽  
R. Gaugler ◽  
R. Harrison

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.


2005 ◽  
Vol 48 (6) ◽  
pp. 911-919 ◽  
Author(s):  
Gláucia Marques Freitas-Ribeiro ◽  
John Furlong ◽  
Viviane Oliveira Vasconcelos ◽  
Cláudia Dolinski ◽  
Alan Loures-Ribeiro

Engorged and partially engorged females of Boophilus microplus were exposed to 600; 3,000; 6,000 and 30,000 infective juveniles of Steinernema carpocapsae Weiser, 1955 Santa Rosa and All strains per dish, under lab conditions. Eggs weight, pre-laying period, laying period, survival period, reproductive efficiency rate, percentage of larval eclosion and lethal concentrations of 50% and 90% (CL50 and CL90) were calculated for engorged females. In the case of partially engorged females, only egg weight, survival period and CL50 and CL90 were calculated. All biological parameters of engorged or partially engorged females were altered by exposition of S. carpocapsae infective juveniles (IJs), Santa Rosa and All strains (p<0.05). The increase in the response was directly proportional to the increase of IJs concentration per Petri dish (p<0.05). Results suggested that entomopathogenic nematodes could have a positive role in the control of cattle tick.


Nematology ◽  
2008 ◽  
Vol 10 (2) ◽  
pp. 251-259 ◽  
Author(s):  
Ernesto San-Blas ◽  
Barbara Pembroke ◽  
Simon Gowen

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.


BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Neil D. Warnock ◽  
Deborah Cox ◽  
Ciaran McCoy ◽  
Robert Morris ◽  
Johnathan J. Dalzell

Abstract Background Steinernema carpocapsae is an entomopathogenic nematode that employs nictation and jumping behaviours to find potential insect hosts. Here we aimed to investigate the transcriptional basis of variant host-finding behaviours in the infective juvenile (IJ) stage of three S. carpocapsae strains (ALL, Breton and UK1), with a focus on neuronal genes known to influence behaviour in other nematode species. Identifying gene expression changes that correlate with variant host-finding behaviours will further our understanding of nematode biology. Results RNA-seq analysis revealed that whilst up to 28% of the S. carpocapsae transcriptome was differentially expressed (P < 0.0001) between strains, remarkably few of the most highly differentially expressed genes (> 2 log2 fold change, P < 0.0001) were from neuronal gene families. S. carpocapsae Breton displays increased chemotaxis toward the laboratory host Galleria mellonella, relative to the other strains. This correlates with the up-regulation of four srsx chemosensory GPCR genes, and a sodium transporter gene, asic-2, relative to both ALL and UK1 strains. The UK1 strain exhibits a decreased nictation phenotype relative to ALL and Breton strains, which correlates with co-ordinate up-regulation of neuropeptide like protein 36 (nlp-36), and down-regulation of an srt family GPCR gene, and a distinct asic-2-like sodium channel paralogue. To further investigate the link between transcriptional regulation and behavioural variation, we sequenced microRNAs across IJs of each strain. We have identified 283 high confidence microRNA genes, yielding 321 predicted mature microRNAs in S. carpocapsae, and find that up to 36% of microRNAs are differentially expressed (P < 0.0001) between strains. Many of the most highly differentially expressed microRNAs (> 2 log2 fold, P < 0.0001) are predicted to regulate a variety of neuronal genes that may contribute to variant host-finding behaviours. We have also found evidence for differential gene isoform usage between strains, which alters predicted microRNA interactions, and could contribute to the diversification of behaviour. Conclusions These data provide insight to the transcriptional basis of behavioural variation in S. carpocapsae, supporting efforts to understand the molecular basis of complex behaviours in nematodes.


Parasitology ◽  
1996 ◽  
Vol 113 (5) ◽  
pp. 473-482 ◽  
Author(s):  
J. F. Campbell ◽  
E. Lewis ◽  
F. Yoder ◽  
R. Gaugler

SUMMARYUnderstanding the temporal and spatial distribution of entomopathogenic nematodes is essential for determining the role of these insect parasites in soil communities and ultimately for their use in suppression of pest insect populations. We measured the vertical and horizontal distribution of endemic populations of entomopathogenic nematodes (Steinernema carpocapsae and Heterorhabditis bacteriophord) in turfgrass. Vertical distribution was determined by taking soil cores every 3 h from 05.00 to 23.00 h, over 4 days, and dividing the cores into 8, 1 cm deep sections. Steinernema carpocapsae was recovered primarily near the soil surface: 50% of positive sections were recovered in the thatch or first 1 cm of soil. S. carpocapsae recovery was lower during the middle of the day and none were recovered in the upper section. H. bacteriophora was recovered uniformly throughout the top 8 cm of soil and its vertical distribution did not change over the course of the day. Horizontal distribution was measured as the number of nematodes recovered from cores taken from 12 randomly selected 0·3 × 0·8 m sections from within four 15·3 × 15·3 m plots. Samples were collected biweekly over a 9-month period. H. bacteriophora had a patchier distribution than S. carpocapsae and both nematode species had more patchy distributions then their potential hosts. Our results support the hypothesis that these two species of nematode utilize different foraging strategies; S. carpocapsae primarily a surface adapted ambusher and H. bacteriophora as a cruise forager.


1997 ◽  
Vol 75 (12) ◽  
pp. 2137-2141 ◽  
Author(s):  
Ganpat B. Jagdale ◽  
Roger Gordon

Four strains of entomopathogenic nematodes were recycled in vivo for 2 years at temperatures ranging from 10 to 25 °C, then the infectivity of their infective juveniles was compared. Infectivity was examined by measuring LC50 values for wax moth (Galleria mellonella) larvae at bioassay temperatures ranging from 5 to 25 °C. Of the four strains examined, only the Umeå and NF strains of Steinernema feltiae that had been recycled at 10 °C infected and killed the insects at a bioassay temperature of 5 °C. The Steinernema carpocapsae All and Steinernema riobravis TX strains were infective at 10 °C only when the recycling temperature was ≤ 20 °C. The infectivity of the two strains of S. feltiae at 10 or 15 °C was compromised by propagating them at higher temperatures (20–25 °C). The Umeå strain of S. feltiae displayed an impaired capacity to infect hosts at higher temperatures (20–25 °C) when recycled at lower (≤ 15 °C) temperatures. The capacity of these nematodes to adjust to different recycling temperatures is discussed in relation to their infectivity in different field situations.


Sign in / Sign up

Export Citation Format

Share Document