Exposure to Ecdysone Agonist-Treated Surfaces Negatively Affects Reproduction and Orientation in Adult Moths

Transcription

1 Exposure to Ecdysone Agonist-Treated Surfaces Negatively Affects Reproduction and Orientation in Adult Moths by Bruce A. Barrett, PhD Entomology Program Area Division of Plant Sciences University of Missouri Columbia, Missouri USA Review Insect Endocrine System Prothoracic glands Corpus allata ecdysone juvenile hormone (JH) Larva - Larva Larva - Pupa Pupa - Adult Types of Molt 1

2 Review Ecdysteroids (e.g., ecdysone) division of epidermal cells Reproduction - stimulate vitellogenesis - stimulate spermatogenesis Growth - initiate evagination of imaginal discs Molting - initiates apolysis - cuticle production Review Ecdysteroid agonist insecticides Tebufenozid e (RH-5992) (RH-2485) Mimic ecdysone and accelerates the molting process resulting in a premature, lethal molt. Mouthparts are trapped within old head capsule and cannot be shed, larva starves to death. 2

3 From the literature... Low doses or exposure to insecticides may result in non-lethal effects on the target organism. Examples: Spruce budworm ( (Choristoneura fumiferana) larvae fed sublethal doses of fenitrothion (OP)... resulted in reduced fecundity in adults (Alford & Holmes 1986). From the literature... Low doses or exposure to insecticides may result in non-lethal effects on the target organism. Examples: Tufted apple bud moth ( (Platynota idaeusalis) ) larvae fed sublethal doses of fenoxycarb (JH mimic)... resulted in reduced fecundity and fertility in adults (Biddinger ( & Hull 1999). 3

4 From the literature... Low doses or exposure to insecticides may result in non-lethal effects on the target organism. Examples: Adult diamondback moths ( (Plutella xylostella) ) sprayed with sublethal does of carbaryl (carbamate carbamate) ) had a decrease in fecundity (Kumar & Chapman 1984). Adult female bollworm ( (Helicoverpa zea) ) treated with sublethal doses of permethrin (synthetic pyrethroid) attracted fewer males than untreated females treated males were less likely to respond to pheromone traps than untreated males (Moore 1988). From the literature... Low doses or exposure to insecticides may result in non-lethal effects on the target organism. Examples: Eastern five-spined ips beetle (Ips grandicollis) Adult California five-spined ips beetle treated with fenoxycarb (JH mimic) had a reduction in fertility (Chen & Borden 1989). 4

5 From the literature... Low doses or exposure to insecticides may result in non-lethal effects on the target organism. Majority of studies on sublethal effects have the insecticide being: USDA-ARS IPBB (Germany) - applied topically - incorporated into diet Few published reports on effects of exposure to treated surfaces. Research Project... Sublethal effects of exposure to surfaces treated with ecdysone agonists on major tortricid apple pests. Codling Moth Oriental fruit Moth Obliquebanded Leafroller Redbanded Leafroller 5

6 Target species... OK State Extension Oriental fruit Moth - Grapholita molesta (Busck) - direct and indirect deciduous fruit pest - major pest of peach and apple - larvae bore into shoots and fruit OFM shoot damage OFM fruit damage Target species... Redbanded Leafroller - Argyrotaenia velutinana (Walker) - indirect/direct deciduous fruit pest - primarily attacks apple - larvae feed of foliage and surface of fruit Obliquebanded Leafroller - Choristoneura rosaceana (Harris) - direct deciduous fruit pest - primarily attacks apple - larvae feed on surface of fruit 6

7 Target species... Codling Moth - Cydia pomonella (L.) - direct deciduous fruit pest - major pest of apple and pear - larvae bore into fruit Egg and neonate Sting Sting damage Entry Entry damage Larvae in in pupation cocoons Internal fruit damage Project A: Effects of ecdysone agonists on moth reproduction. Codling moth Redbanded leafroller Obliquebanded leafroller (Cydia pomonella) (Argyrotaenia velutinana) (Choristoneura rosaceana) Objective: with Determine what effects adult exposure to surfaces treated ecdysone-agonists would have on moth fecundity and fertility. 7

8 Project A: Effects of ecdysone agonists on moth reproduction. Codling moth Redbanded leafroller Obliquebanded leafroller (Cydia pomonella) (Argyrotaenia velutinana) (Choristoneura rosaceana) Assay #1 Continuous exposure Virgin adults (<48 ( h old) placed in cage (1F, 2M) lined with treated mesh screening. Oviposition sites were treated apple or foliage; egg counts every 24 h until female death. Assay #1 Continuous exposure (both sexes) Cydia pomonella Argyrotaenia velutinana Choristoneura rosaceana Mean Fecundity Control Tebufenozide 74.5 a 39.6 b 17.5 c a 62.5 b 51.9 b a b b Mean % Fertility Control Tebufenozide 58.4 a 6.6 b 0.4 c 83.7 a 29.7 b 9.5 c 86.4 a 29.3 b 7.6 c Means followed by the same letter in the same column per parameter er are not significantly different (Fisher s s PLSD Test, P<0.05; Continuity Adjusted Chi-Square Test, P<0.05) Journal of Economic Entomology 92: Entomologia Experimentalis et Applicata 94:

9 Project A: Effects of ecdysone agonists on moth reproduction. X Reproduction of a treated moth paired with a nontreated moth? Assay #2 Treated x Nontreated Pairings Virgin adults (<48 ( h old) placed in treated cage (by sex). After 24 h, paired with nontreated partner in nontreated cage with apple or plastic strips (oviposition sites). Egg counts every 24 h until female death. Assay #2 Treated x Nontreated Pairings Cydia pomonella Argyrotaenia velutinana Choristoneura rosaceana Mean Fecundity Control Tebufenozide-M Tebufenozide-F -M -F 97.7 a 65.5 ab 26.8 b 39.1 b 21.9 b 84.0 a 59.7 a 47.4 a 56.2 a 4.2 b a b 6.4 c 48.8 c 1.2 c Mean % Fertility Control Tebufenozide-M Tebufenozide-F -M -F 86.3 a 87.6 a 78.7 b 74.4 b 79.0 b 73.0 b 78.7 a 66.8 c 50.5 d 4.6 e 74.9 a 52.8 b 13.0 c 76.7 a 18.8 c Means followed by the same letter in the same column per parameter er are not significantly different (Fisher s s PLSD Test, P<0.05; Continuity Adjusted Chi-Square Test, P<0.05) Journal of Economic Entomology 92: Entomologia Experimentalis et Applicata 94:

10 Project A: Effects of ecdysone agonists on moth reproduction. Key results 1. The mean fecundity and fertility of adult moths exposed to treated t surfaces of tebufenozide and methoxyfenozide (at field rates), whether for entire e life or for 24 hr, are significantly reduced. 2. had a significantly greater affect in reducing adult moth fertility than tebufenozide. 3. Depending on species, the negative influence of tebufenozide on adult fecundity and fertility appears to be female-based. 4. Depending on species, the negative influence of methoxyfenozide on adult fecundity and fertility appears to be both male- and female-based. 5. Constant exposure to methoxyfenozide-treated treated surfaces significantly reduced the longevity of adult male moths. Ecdysteroids (e.g., ecdysone) division of epidermal cells Reproduction - stimulate vitellogenesis - stimulate spermatogenesis Growth - initiate evagination of imaginal discs Molting - initiates apolysis - cuticle production Mating Behavior 1. Chemical communication A. Exocrine glands: - produce sex pheromones - located beneath cuticle B. Chemoreceptors: - found on antennae, MP, legs 10

11 Project B: Effects of ecdysone agonists on moth orientation. (After Haynes & Birch 1985) Objective: Determine what effects adult exposure to surfaces treated with ecdysone-agonists would have on female attractiveness and male responsiveness. Project B: Effects of ecdysone agonists on moth orientation. Assay #1: Wind Tunnel Virgin moths (0-24 h old) placed in cages with a treated liner for 48 h. 4.5 x 9 cm The liners were treated with, surfactant or methoxyfenozide. Moths were then exposed to wind tunnel tests. Wind Tunnel Combinations Female Male surfactant surfactant 3. methoxyfenozide surfactant 4. methoxyfenozide methoxyfenozide 5. surfactant methoxyfenozide Exposure cages with plastic-mesh liners. Wind tunnel at Horticulture and Agroforestry Research Center. 11

12 Project B: Effects of ecdysone agonists on moth orientation. Assay #1: Wind Tunnel Female calling calling cage (w/4-5 5 females) placed upwind, male release release cage (8-10 males) placed 1 m downwind. Upwind female calling platform. Downwind male release cage. Project B: Effects of ecdysone agonists on moth orientation. Assay #1: Wind Tunnel Female calling calling cage (w/4-5 5 females) placed upwind, male release release cage (8-10 males) placed 1 m downwind. Upwind female calling platform. Motion JPEG OpenDML decompressor Smoke tests using titanium tetrachloride (TiCl ) confirmed 4 plume position (laminar flow) within wind tunnel. Downwind male release cage. 12

13 Project B: Effects of ecdysone agonists on moth orientation. Assay #1: Wind Tunnel After acclimation period males released, and 20 min later number of trapped males recorded. Upwind female calling cage and male trapping platform. Assay #1: Wind Tunnel Wind Tunnel Combinations Cydia pomonella Mean % of Males Recaptured Argyrotaenia velutinana Choristoneura rosaceana Female Male ab 23.3 a 33.9 a 2. surfactant a surfactant 39.5 a 14.4 b 18.5 b 3. b surfactant 36.3 ab 15.3 ab 29.4 a c 7.9 c 12.5 b 5. surfactant 27.5 bc 5.8 c 15.1 b Means followed by the same letter are not significantly different t (Fisher s s PLSD, P<0.05) a Labeled field rate (0.125% vol:vol) of Latron B-1956 B b Each methoxyfenozide treatment solution contained the surfactant (as per label recommendations). Journal of Economic Entomology 96: Entomologia Experimentalis et Applicata 107:

14 Assay: Wind Tunnel (2005 study) Oriental fruit moth Level of OFM Attractiveness & Responsiveness. Mean % Male Recapture Female Attractiveness/treatment (male data pooled) (Grapholita molesta) Water Surfactant 41.5 a 39.8 a 31.8 a Male Responsiveness/treatment (female data pooled) Water Surfactant 42.1 a 44.0 a 27.1 b Journal of Economic Entomology 100: Project B: Effects of ecdysone agonists on moth orientation. Assay #2: Orientation Tubes Virgin moths (0-24 h old) placed in cages with treated liner for 48 h. 2.5 x 6 cm Female cages attached to upwind end of tube, male cages attached to downwind end. Observations made on male sexual behavior and distances traveled in tubes. Exposure cage with plastic-mesh liner. Glass orientation tubes inside wind tunnel. Male OBLR approaching caged female. 14

15 Assay #2: Orientation Tubes Wind Tunnel Combinations Mean % of Male Wingfanning and Upwind Orientation c (< 1 min) Cydia Argyrotaenia Choristoneura pomonella velutinana rosaceana Female Male a 60 a 93 a 2. surfactant a surfactant 50 ab 55 a 90 a 3. b surfactant 40 b 57 a 93 a b 23 b 63 b 5. surfactant 38 b 33 b 53 b Means followed by the same letter are not significantly different t (Fisher s s PLSD, P<0.05) a Labeled field rate (0.125% vol:vol) of Latron B-1956 B b Each methoxyfenozide treatment solution contained the surfactant (as per label recommendations). c Behaviors associated with tortricid male moth sexual excitability. Journal of Economic Entomology 96: Entomologia Experimentalis et Applicata 107: Assay #2: Orientation Tubes Wind Tunnel Combinations Cydia pomonella Mean Distance (cm) Traveled (< 1 min) Argyrotaenia velutinana Choristoneura rosaceana Female Male a 65 a 70 a 2. surfactant a surfactant 45 a 52 a 63 a 3. b surfactant 33 ab 47 a 63 a b 8 b 23 b 5. surfactant 13 b 5 b 18 b Means followed by the same letter are not significantly different t (Fisher s s PLSD, P<0.05) a Labeled field rate (0.125% vol:vol) of Latron B-1956 B b Each methoxyfenozide treatment solution contained the surfactant (as per label recommendations). Journal of Economic Entomology 96: Entomologia Experimentalis et Applicata 107:

16 Project C: Effects of ecdysone agonists on moth orientation. Oriental fruit moth (Grapholita molesta) Objective: Examine sexual orientation behaviors of males (nontreated and treated) when given a choice of competing pheromone sources (nontreated and treated females) in a wind tunnel. Project C: Effects of ecdysone agonists on moth orientation. Assay: Competing Pheromone Sources Virgin OFM moths (0-24 h old) placed in cages with a treated liner for 48 h. 4.5 x 9 cm The liners were treated with, surfactant and methoxyfenozide. Two female cages placed upwind in wind tunnel. Single male release cage downwind. Exposure cage with plastic-mesh liners. Motion JPEG OpenDML decompressor Motion JPEG OpenDML decompressor Male OFM orienting to calling females. 16

17 Assay: Competing Pheromone Sources Time Male OFM released in wind tunnel spent displaying sexual excitability behaviors. Mean Time (seconds) Female Treatments (male data pooled) Upwind Plume Orientations Male Treatments (female data pooled) Water 21.7 a 13.4 a Surfactant 13.2 bc 21.9 a 8.3 c 7.9 b Female Cage Contact Water 28.5 a 28.5 a Surfactant 25.4 ab 34.1 a 17.3 b 8.5 b Journal of Economic Entomology 100: Projects B & C: Effects of ecdysone agonists on moth orientation. (After Haynes & Birch 1985) Key results 1. Males exposed to methoxyfenozide-treated treated surfaces were not as responsive (via flight or walking) to calling females as were nontreated males. 2. Females exposed to methoxyfenozide-treated treated surfaces were just as attractive as nontreated females. 3. Disruption of moth orientation through exposure to surfaces treated with methoxyfenozide appears to be male-based. 4. Depending on species, exposure to surfactant-treated treated surfaces also negatively impacts moth orientation. 17

18 Projec t A: Projects B & C: Effects of ecdysone agonists on moth reproduction. Effects of ecdysone agonists on moth orientation. Potential Impacts? Significant population reduction pressures? Negative effects on adult chemical communication in the field? Potential Impacts? Possible misdiagnosis of moth populations with pheromone traps (underestimating male density)? 18

19 Potential Impacts? Possible misdiagnosis of moth populations with pheromone traps (underestimating male density)? Monitoring problems further exacerbated when ecdysone agonists are used in conjunction with mating disruption? USDA-ARS The full utilization of ecdysone agonists in tree fruit pest management agement programs is dependent on better understanding the sublethal impacts these types of insecticides have on the adult (non-target) stage. Acknowledgments Dr. Xiaoping Sun, University of Missouri Ms. Jennifer Hoelscher, Missouri Highway Patrol Lab Mr.. Michael Reinke,, Michigan State University Dr. Mark Ellersieck, University of Missouri Mr. Randy Thiessen, University of Missouri Mr. Kevin Bishop, University of Missouri Dr. David Biddinger, Pennsylvania State University This research was funded through contributions from: Rohm and Haas Company Missouri Apple Merchandising Council Missouri Agricultural Experiment Station Images (slide #4) used with kind permission of HortNET,, a product of The Horticulture and Food Research Institute of New Zealand Limited. 19

20 Questions? 20

21 Review Insect Endocrine System Prothoracic glands Corpus allata ecdysone juvenile hormone Insert field trap data with treated females And get OFM data from Mike s work. Subsequent electroantennagram studies have indicated that (at least for A. V.) the male antennae are still sensitive to the main components of the pheromone (Haynes & Barrett, unpublished data). 21

22 Sublethal exposure to various chemicals has been reported to negatively impact the mate-locating process of moths (Floyd & Crowder 1981, Linn & Roelofs 1984, Haynes 1988, Moore 1988). The full utilization of ecdysone agonists in tree fruit pest management agement programs is dependent on better understanding the sublethal impacts these types of insecticides have on the adult (non-target) stage. Orientation tube assay Cydia pomonella Exposure to treatment surfaces (by sex) a,b Mean % wing fanning, upwind orientation d Mean distance traveled (cm) Female Male <1 min 10 min <1 min 10 min a 55.0a 42.5a 98.1a 2. /surfactant c /surfactant 50.0ab 53.1a 45.0a 92.1a 3. /surfactant 40.0b 64.0a 32.5ab 96.3a b 18.6b 12.5b 47.1b 5. /surfactant 37.5b 20.1b 12.5b 48.3b Means followed by the same letter are not significantly different (Fisher s PLSD, P<0.05) a Female or male moths, h old, exposed to treated surfaces for 48 h prior to being assayed. sayed. c Labeled field rate (0.125% vol:vol) of Latron B-1956B b Twenty (20) cages (replicates)/trmnt; each consisted of 2 caged F and 2 released M. New moths used each replicate. d Behaviors associated with tortricid male moth sexual excitability. 22

23 Orientation tube assay Argyrotaenia velutinana Exposure to treatment surfaces (by sex) a,b Mean % wing fanning, upwind orientation d Mean distance traveled (cm) Female Male <1 min 10 min <1 min 10 min a 56.8a 65.0a 83.8a 2. /surfactant c /surfactant 55.0a 65.5a 51.7a 88.0a 3. /surfactant 56.7a 62.8a 46.7a 88.0a b 43.0b 8.3b 64.8b 5. /surfactant 33.3b 41.5b 5.0b 62.5b Means followed by the same letter are not significantly different (Fisher s PLSD, P<0.05) a Female or male moths, h old, exposed to treated surfaces for 48 h prior to being assayed. sayed. c Labeled field rate (0.125% vol:vol) of Latron B-1956B b Twenty (20) cages (replicates)/trmnt; each consisted of 2 caged F and 2 released M. New moths used each replicate. d Behaviors associated with tortricid male moth sexual excitability. Orientation tube assay Choristoneura rosaceana Exposure to treatment surfaces (by sex) a,b Mean % wing fanning, upwind orientation d Mean distance traveled (cm) Female Male <1 min 10 min <1 min 10 min a 75.3a 70.0a 103.8a 2. /surfactant c /surfactant 90.0a 62.1b 62.5a 106.4a 3. /surfactant 92.5a 80.1a 62.5a 100.8a b 31.4c 22.5b 58.8b 5. /surfactant 52.5b 19.0c 17.5b 55.0b Means followed by the same letter are not significantly different (Fisher s PLSD, P<0.05) a Female or male moths, h old, exposed to treated surfaces for 48 h prior to being assayed. sayed. c Labeled field rate (0.125% vol:vol) of Latron B-1956B b Twenty (20) cages (replicates)/trmnt; each consisted of 2 caged F and 2 released M. New moths used each replicate. d Behaviors associated with tortricid male moth sexual excitability. 23