A preliminary study was conducted to determine if the rove beetle, Paederus littorarius Grav., would exhibit a feeding preference for the eggs of the pyralid moth, Chrysoteuchia topiaria Zeller, a pest in Wisconsin cran­berry bogs. Individuals were offered a choice of C. topiaria eggs or Drosophila sp. adults for four days. Total number of prey items eaten was converted to weight using a multiplier based on the mean weight of 20 individuals of each prey item, respectively. A significant preference for Drosophila adults was observed in the preference trial; however as many as 24 C. topiaria eggs in addition to Drosophila offerings were consumed by P. littorarius individuals within a 24 h period. Additionally, laboratory and field observations suggests P. littorarius is a polyphagous predator

Haase-Statz, Sandra

English

Valparaiso University

The Great Lakes Entomologist Volume 30 Number 3 - Fall 1997 Number 3 - Fall 1997 Article 5 October 1997 Evaluation of Paederus Littorarius (Coleoptera: Staphylinidae) as an Egg Predator of Chrysoteuchia Topiaria (Lepidoptera: Pyralidae in Wisconsin Cranberry Bogs Sandra Haase-Statz University of Wisconsin Follow this and additional works at: https://scholar.valpo.edu/tgle Part of the Entomology Commons Recommended Citation Haase-Statz, Sandra 1997. "Evaluation of Paederus Littorarius (Coleoptera: Staphylinidae) as an Egg Predator of Chrysoteuchia Topiaria (Lepidoptera: Pyralidae in Wisconsin Cranberry Bogs," The Great Lakes Entomologist, vol 30 (2) Available at: https://scholar.valpo.edu/tgle/vol30/iss2/5 This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. For more information, please contact a ValpoScholar staff member at scholar@valpo.edu. ........._-_....._----------------------------------_.­THE GREAT lAKES ENTOMOLOGIST1997 93 EVALUATION OF PAEDERUS UTTORARIUS (COLEOPTERA:STAPHYLINIDAE) AS AN EGG PREDATOR OF CHRYSOTEUCHIA TOPIARIA (LEPIDOPTERA: PYRALIDAEl IN WISCONSIN CRANBERRY BOGS Sandra Haase-Statz 1 ABSTRACT A preliminary study was conducted to determine if the rove beetle, Paederus littorarius Grav., would exhibit a feeding preference for the eggs of the pyralid moth, Chrysoteuchia topiaria Zeller, a pest in Wisconsin cran­berry bogs. Individuals were offered a choice of C. topiaria eggs or Drosophila sp. adults for four days. Total number of prey items eaten was converted to weight using a multiplier based on the mean weight of 20 indi­viduals of each prey item, respectively. A significant preference for Drosophila adults was observed in the preference trial; however as many as 24 C. topiaria eggs in addition to Drosophila offerings were consumed by P. littorarius individuals within a 24 h period. Additionally, laboratory and field observations suggests P. littorarius is a polyphagous predator. The cranberry girdler, Chrysoteuchia topiaria Zeller (Lepidoptera: Pyrali­dae) is a sporadic but important pest of cranberries Vaccinium macrocarpum Aiton. Larvae attack the plant by chewing the underground stems and dis­rupting nutrient flow. Control of this pest can be problematic for several r a­sons. First, larvae may be overlooked because damage is not usually seen until the spring following attack. Second, the larval stage is spent hidden in the leaf litter and soil, and is difficult to monitor. Lastly, the adult, which can be monitored during its 6-8 week flight period, can not be controlled with pesicide applicat ons because the pest's flight period coincides with host plant blossoming. Chemical control can not be used when cranberries are in blossom due to the neccessity of pollinator activity (Roberts 1983, Mahr and Moffitt 1994). . The rove beetle, Paederus littorarius Gravenhorst, is a common endemic predator of small arthorpods in North American riparian habitats. It is a polyphagous and opportunistic predator which consumes a variety of prey items in the laboratory (S. Haase-Statz unpublished data). Paederus spp. are extra-oral feeders that attack their prey and suck the hemolymph from the body, and discard the exoskeleton. They feed on all life stages of other insects but have been shown to have a preference for eggs and early instar larvae (Ahmed 1957, Kurosa 1958, Manley 1977). However, there is no published in­formation specifically regarding the feeding habits of North American Paederus, nor has there been any work evaluating them as predators in North American agricultural systems. IDepartment of Entomology, University of Wisconsin, Madison, WI 53706. 1Haase-Statz: Evaluation of Paederus Littorarius (Coleoptera: StaphyliniPublished by ValpoScholar, 199794 THE GREAT LAKES ENTOMOLOGIST Vol. 30, No.3 Paederus spp. in Asia, the Middle East and South America have been identified as important predators of a variety of agriculturally significant phytophagous insects. For example, P. alferii Koch has been effective in con­trolling many cotton pests, P. fuscipes Curtis is important in the control of several rice pests, and P. columbinus is effective against sugar cane pests. Additionally, Paederus spp. occur in clover, maize, peas, beans, potatoes and banana plantations (Frank and Kanamitsu 1987). The objective of this study was to conduct a preliminary evaluation of P. littorarius as a predator in an agricultural system important to Wisconsin. The cranberry system was chosen based on its riparian nature which pro­vides suitable habitat for Paederus spp. Additionly, P. littorarius had been collected in pitfall tra s placed in cranberry bogs, establishing their occur­rence there (Coffield unpublished data). Chrysoteuchia topiaria was selected as the target pest for two reasons: (1) C. topiaria eggs are oviposited randomly on the s il surface of the bog and larvae are found in the leaf litter under the cranberry vines (Roberts, 1983). P. littorarius is commonly found in leaf litter scavenging on the soil surface where it forages; (2) C. topiaria eggs and larvae are present when adult and larval Paederus are actively foraging. The study was conducted to answer the following questions: Will P. littorarius feed on C. topiaria eggs? What is the rate of consumption? And will P. littorarius preferentially feed on C. topiaria eggs? METHODS To determine whether P. littorarius would feed on Chrysoteuchia eggs and if so, at what rate consumption occurred, adult beetles was placed in 5" petri dishes; one per petri dish. Each petri dish was lined with damp filter paper. Beetles were then starved for 24 h. Sixty Chrysoteuchia eggs were placed in each petri dish and the beetles were given 24 h to fe d. Remaining food items were removed and counted to determine total number eaten. One replicate was completed. The average number of eggs eaten per beetle for 2 d was calculated. To determine if P. littorarius would feed preferentially on Chrysoteuchia eggs, the predators were offered a choice between the targ t prey and frozen Drosophila adults. Drosophila were used as the alternative prey item be­cause they had been used to successfully rear P. littorarius and were avail­able. This trial used ten female P. littorarius and was conducted over four days. Comparisons were based on mean consumption of each individual over 4 days. The predators were placed in individual petri dishes with wet filter paper. Each was starved initially for 24 h a d subsequently starved for 6 h between feedings. Beetles were given 24 h to feed. R maining pr y items then were removed and counted. The umber eaten was converted to mass using a multiplier (Drosophila =0.8253 mg; C. topiaria eggs 0.0357 mg). The multiplier for each prey item was determined by weighing 20 individuals of each prey item and calculating the mean weight per prey item. At the first feeding, two (» 1.4 mg) Drosophila and 15 (" 0.6 mg) Chrysoteuchia eggs were placed in each petri dish. E ght of the ten beetles consumed all of the prey items in the first feeding; therefore, five Drosophila (» 4.0 mg ) and 25 (» 1.0 mg) Chrysoteuchia eggs were placed in ach dish for subsequent feedings. The null hypothesis that there was no preferential feeding was tested using a t-test for paired means. The statistical expert in Quattro Pro 5.0 soft­ware (MS-DOS version by Borland International, 1994) was used to analyze the data. 2The Great Lakes Entomologist, Vol. 30, No. 2 [1997], Art. 5https://scholar.valpo.edu/tgle/vol30/iss2/5-THE GREAT LAKES ENTOMOLOGIST1997 95 Adult P. littorarius used for the trials were rear d from field collected adults. C. topiaria eggs were obtained from field collected adults using the methods of Roberts (1983). Drosophila were obtained from a genetics lab at the University of Wisconsin-Madison. RESULTS Paederus littorarius adults began feeding on C. topiaria eggs immedi­ately after they were placed in the containers. The m an number of eggs con­sumed in 24 h was 31.5 ± 11.16, range was 21-54 (n=lO for 2 trials). In the preference trial, ten adult female P. littorarius ate between 0-22 eggs per day (Table 1), an average of 8.93 eggs (0.319 ± 0.16 mg) (Fig. 1); and between 0-4 Drosophila (Table 1), an average of 2.54 adults (2.094 ± 0.38 mg) (Fig. 1). The t-test showed a significant preference for Drosophila (p <0.00001). DISCUSSION In the non-preference test, Paederus adults were shown to feed readily on the eggs of C. topiaria. However, they showed a marked preference for Table 1. Daily prey consumption by Paederus littorarius. Each beetle was provided five Drosophila and 25 Chrysoteuchia topiaria eggs simult neously. Number ofDrosophila eaten per day Beetle 1 Day 2 3 4 Mean Mean Wt 1 2 3 4 0 2.25 (±1.5) 1.86 (±1.2) 2 2 3 3.5 3 2.88 (±0.5) 2.37 (±0.4) 3 2 4 3 4 3.25 (±0.8) 2.68 (±0.7) 4 2 3 1.5 2 2.13 (±0.5) 1.75 (±OA) 5 2 3.5 5 2 3.13 (±1.2) 2.58 (±l.O) 6 2 3 2 1 2.00 (±0.7) 1.65 (±0.6) 7 2 2 4 0 2.00 (±1.4) 1.65 (±1.2) 8 2 4 4 1 2.75 (±1.3) 2.27 (±l.1) 9 1.5 4 3 0 2.13 (±1.5) 1.93 (±1.3) 10 1.5 3 4 3 2.88 (±0.9) 2.75 (±0.7) Number ofChrysoteuchia topiaria eggs eaten per day 1 15 20 11 16 15.50 (±3.2) 0.55 (±0.1) 2 7 0 3 0 2.50 (±2.9) 0.09 (±0.1) 3 1 1 15 6 5.75 (±5.7) 0.21 (±0.3) 4 1 1 19 7 7.00 (±7.3) 0.25 (±0.3) 5 15 0 4 0 4.75 (±6.1l 0.17 (±0.2) 6 14 0 4 13 7.75 (±5.9) 0.28 (±0.2) 7 18 14 14 22 17.00 (±3.3) 0.61 (±0.1) 8 16 7 0 1 6.00 (±6.4) 0.21 (±02) 9 18 16 4 8 11.50 (±5.7) 0.41 (±0.2) 10 14 15 8 9 11.50 (±3.0) 0.41 (±0.1) 3Haase-Statz: Evaluation of Paederus Littorarius (Coleoptera: StaphyliniPublished by ValpoScholar, 1997..-., en E '-' c:: o a 4 3 § 2 en c:: o () c:: ca (!) ~ 1 o --l j T if j [II I 1 \ ~ T I T -~ ;r n~~ tW tL­96 THE GREAT lAKES ENTOMOLOGIST Vol. 30, No.3 1 2 3 4 5 6 7 8 9 10 Beetles I ===:J Chrysoteuchia I I Drosophila I Figure 1. Consumption ofDrosophila adults and Chrysoteuchia topiaria eggs, expressed in milligrams of prey over a period f four days. Each beetle was provided with five Drosophila and 25 C. topia ria eggs daily. Drosophila adults when given a choice. There are several possible explana­tions for this strong showing of preference: (1) P. littorarius truly prefer Drosophila over all ther prey items; (2) hey prefer small dipteran prey over other types; (3) there is an energy benefit to taking a few large prey items over several small prey items; or (4) the individual predators had developed an artificial preference for Drosophila from having been reared and main­tained on this food source. Additional information about the feeding habits of P. littorarius was 4The Great Lakes Entomologist, Vol. 30, No. 2 [1997], Art. 5https://scholar.valpo.edu/tgle/vol30/iss2/5THE GREAT LAKES ENTOMOLOGIST1997 	 97 gathered during rearing studies. Field collected adults were maintained on a variety of food sources which included: small dipteran adults (Chironomidae and Cecidomyiidae), Collembola and hemipterans (Cicadellidae and Cercopi­dae) reared adventitiously from soil obtained at Paederus collection sites; early instar larvae of Plodia interpunctella Hubner (Pyralidae) and Psuedo­plusia includens Walker (Noctuidae); various large dipteran larvae (Cal­liphoridae, Sarcopha 'dae, Muscidae); and a variety of other odd offerings (eg. roast beef, ch cheese, and bran muffin). thus supporting the as­sumption that P. littorarius is a polyphagous predator. It should be noted, however, that P. littorarius did not thrive on many of these prey items and Drosophila was the only pre item that has been successfully used to rear Wisconsin Paederus pp. in the lab (S. Haase-Statz, unpublished data). It is unknown if P. littorarius contributes to the control of C. topiaria. It is probably an important part of the natural enemy complex for this pest. Field observation and collection data for P. littoranus indicate that they are found in a variety of moist habitats, including wet meadows, marshes, bogs, roadside ditches and leaf litter such as are found within and surrounding cranberry beds. As stated earlier, a few adult P. littorarius were collected in pitfall traps placed within cranberry beds located near Warrens, Wisconsin, in 1991 (Cockfield, unpubL). I surveyed eight commercial cranberry beds lo­cated on three differenct cranberry farms. Although I was not successful in locating any additional specimens in the beds, I did collect Pae erus littorar­ius in grass adjacent to beds and along streams and drainage ditches in the vacinity of commercial cranberry production. Based on collection data, it seems reasonable to assume that P. litt rar­ius is more likely to be found in unmowed grassy areas around cranberry beds than in the beds themselv s. Kamm et aL (1983) concluded that the cranberry girdler prefers grassy areas surrounding cultivated areas, and leave that habitat when it becomes undesirable. Therefore, P. littorarius could be useful in regulating cranberry girdler populations in source habi­tat . ACKNOWLEDGMENTS I thank Dr. Daniel Mahr for advice on this project, Jane Soijka for infor­mation regarding cranberry girdler outbreaks, and all the growers who al­lowed access to their property. This study was supported in part by Hatch Grant WS-03570 to Dr. Daniel KYoung. LITERATURE CITED Ahmed, M. K 1957. Life-history and feeding habits of Paederus alfierii Koch (Coleoptera: Staphylinidae). Bull. Soc. Entomol. Egypte 41: 129-143. Frank, J. H., and Kanamitsu. K 1987. Paederus, sensu lato (Coleoptera: Staphylin­idae): natural history and medical importance. J. Med. Entomol. 24 (2): 155-19l. Kamm, J. A., P. D. Morgan, D. L. Overhulser, L. M. McDonough, M. Triebwasser, and L.N. Kline. 1983. Management practices for cranberry girdler (Lepidoptera: Pyrali­dae) in Douglas-fir nursey stock. J. Econ. Entomol. 76: 923-926. Kurosa, K 1958. Studies on poisonous beetles. III. Studies on the life history of Paederus fuscipes Curtis (Staphylinidae). Japan. J. Sanit. Zool. 9: 245-76. :".!ahr, S. E. 	R. and L. J. Moffitt. 1994. Biologic and Economic Assessment of Pesticide Usage on Cranberry. NAPIAP Report Number 2-CA-94. 5Haase-Statz: Evaluation of Paederus Littorarius (Coleoptera: StaphyliniPublished by ValpoScholar, 199798 THE GREAT LAKES ENTOMOLOGIST Vol. 30, No.3 Manley, G. V. 1977. Paederus fuscipes (Coleoptera: Staphylinidae): a predator of rice fields in West Malaysia. Entomophaga 22: 47-59. Roberts, S. L. 1983. Studies of the Cranberry Girdler Chrysoteuchia topiaria in Wis­consin. M.S. thesis, Univeristy of Wisconsin-Madison. Roberts, S. L., and D L. Mahr. 1986. Development of Cranberry Girdler, Chrysoteuchia topiaria (Lepidoptera: Pyralidael in relation to temperature. Great Lakes Entomol. 19 (2): 85-90. 6The Great Lakes Entomologist, Vol. 30, No. 2 [1997], Art. 5https://scholar.valpo.edu/tgle/vol30/iss2/5

Evaluation of \u3ci\u3ePaederus Littorarius\u3c/i\u3e (Coleoptera: Staphylinidae) as an Egg Predator of \u3ci\u3eChrysoteuchia Topiaria\u3c/i\u3e (Lepidoptera: Pyralidae in Wisconsin Cranberry Bogs

Evaluation of \u3ci\u3ePaederus Littorarius\u3c/i\u3e (Coleoptera: Staphylinidae) as an Egg Predator of \u3ci\u3eChrysoteuchia Topiaria\u3c/i\u3e (Lepidoptera: Pyralidae in Wisconsin Cranberry Bogs

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