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Diurnal activity of soil-surface arthropods in agroecosystems: Design for an inexpensive time-sorting pitfall trap
Agriculture, Ecosystems and Environment, 20 (1988) 159-164
159
Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands
Diurnal Activity of Soil-Surface Arthropods in Agroecosystems: Design for an Inexpensive TimeSorting Pitfall Trap ANDREA Y. BLUMBERG 1 and D.A. CROSSLEY, Jr. ~
lOffice of Agriculture, Bureau for Science and Technology, Agency for International Development, Washington, DC 20523 (U.S.A.) 2Department of Entomology and Institute of Ecology, University of Georgia, Athens, GA 30602 (U.S.A.) (Accepted for publication 13 October 1987)
ABSTRACT
Blumberg, A.Y. and Crossley, Jr., D.A., 1988. Diurnal activity of soil-surface arthropods in agroecosystems: design for an inexpensive time-sorting pitfall trap. Agric. Ecosystems Environ., 20: 159-164. The design for an inexpensive time-sorting pitfall trap is presented. The basis of the mechanism is a rotary stepping solenoid powered by lantern batteries. Traps were utilized to sample soilsurface arthropods at 2-h intervals for five 24-h periods in 1983. One trap was placed in a conventional tillage (CT) agroecosystem and one in a no-•lage (NT) agroecosystem. Soft arthropod surface activity was greatest in CT on 19 July during the dawn and dusk periods and during dusk on 27 June.
INTRODUCTION
Comparison of pitfall trap catches in different habitats affords a measure of the relative activities of surface-dwelling soil arthropods. Pitfall trapping is a widely used technique for collecting arthropods, but it is not quantitative. The number of arthropods caught is influenced not only by density but also by activity {Williams, 1959; Greenslade, 1964; Dondale et al., 1972; Granstrom, 1973 ). Activity is influenced by both mobility of the arthropod and the nature of the substrate. Pitfall trapping has been quantified by removal methods ( Gist and Crossley, 1973 ) and by mark-recapture techniques (Southwood, 1978 ). Otherwise, pitfall trapping has been used successfully as a comparison method of evaluating differences between ecosystems (Muma, 1973; Hagvar et al., 1978; Blumberg and Crossley, 1983). Diurnal activities of surface-dwelling soil arthropods can be evaluated with pitfall traps but the method is laborious. Ad0167-8809/88/$03.50
© 1988 Elsevier Science Publishers B.V.
160
Funn:.--~_oil. Surface ~-----'~ ]1/4tSoil to Top of Funnel
SampleCups Rot ary Stepping Solenoid
~
~
~
~
Batteries
TimingCircuit Fig. 1. Schematic diagram of the trapping system. The trap mechanism is housed in an aluminum box.
ditionally, the effect of trap manipulation on faunal activity in the immediate area is unknown. Presented here are the design and evaluation of a time-sorting pitfall trap which automatically changes sample cups at 2-h intervals. The trap contains 16 cups, so that a 32-h continuous sampling can be performed. The design was evaluated with measurement of diurnal activity of soil-surface arthropods in conventional tillage and continuous no-tillage grain sorghum agroecosystems. METHODS AND MATERIALS
Trap design The trap and its mechanism are enclosed in a small metal box (31 X 31 X 26 cm). The time-sorting feature permits a fresh sample cup to be rotated under the trap funnel at periodic intervals (Fig. 1 ). An aluminum housing encloses a turntable (28.5 cm in diameter) supporting the sample cups. A rotary stepping solenoid rotates the turntable at 22.5 ° intervals (16 cups total) and is powered by a set of 6-V lantern batteries. Solid state circuitry generates timed pulses and energizes the solenoid. The turntable and all fabricated metal parts are aluminum. The cups are 60ml Tupperware ® containers bolted through the turntable, A second inner cup containing ethylene glycol is inserted to hold the actual samples.
161 vcc
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556
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\
.1
Fig. 2. Schematic diagram of timing circuit. (C1 = 500 uF; C2-- 0.01 uF; D1 -- 1N4003; D2 = 1N4003; RA=2.2 M; RB=3.3 M; R c = 2 0 M).
Timing circuit The timing circuit incorporates a dual timer 556 chip (Fig. 2 ). One section operates in an astable mode, generating pulses. The frequency is determined by resistor and capacitor combinations, and can be manually triggered (or reset) by a momentary SPST ($2 in Fig. 2). These pulses trigger the other timer which operates in a monostable mode to generate resistor/capacitor controlled pulses of sufficient duration to permit the solenoid to advance one complete step. The output switches a transistor which energizes a small relay which activates the solenoid.
Solenoid and batteries The rotary stepping solenoid is a 28-V DC surplus unit. An SPST switch ($3 in Fig. 2) can disable the solenoid during testing and timing calibration in order to minimize battery use. A small hub was fitted around the switch shaft using Allen screws. This arrangement provided a threaded shaft, so that a nut could be tightened on the turntable. Five 6-V lantern batteries were connected in series and tapped to provide 30 V for the solenoid, 24 V for the relay and 12 V for the timing circuit. However, the battery voltage dipped significantly when the solenoids were energized, so
162
a separate 9-V source controlled by an SPST switch ($1 in Fig. 2) was added to energize the timing circuit. The use of screw terminal batteries facilitates battery replacement. Field evaluation
The aluminum housing is buried so that the top is slightly below the soil surface. A funnel is placed in a hole in the housing lid so that it is directed over the center of a sample cup. The housing lid is covered with soil ( and litter in N T systems). The trap is allowed to run for at least 14 h; the first cup is discarded in order to avoid the effects of disturbance when the trap is set for use.
Automated traps were evaluated in no-tillage ( N T ) and conventional tillage (CT) grain sorghum at the University of Georgia's Horseshoe Bend facility (Blumberg and Crossley, 1983). Test operations were performed during five 24-h periods between 27 June and 13 September 1983. Two traps were used, one in the CT agroecosystem and one in the N T agroecosystem. The plots used were planted in grain sorghum. Both plots were planted with winter rye the previous winter. The CT plot was ploughed and disked prior to sorghum planting; the NT plot was not cultivated at any time, so that a layer of rye mulch was present on the soil surface. The traps were allowed to 'settle' for 3 weeks prior to use, in order to minimize the effects of disturbance from the installation. RESULTS AND DISCUSSION
Numbers captured during the 2-h periods for the five sample dates in 1983 are shown in Fig. 3 (CT) and 4 ( N T ) The first time period represents a 2-h period from midnight to 2 am. The largest catches in CT occurred on 19 July during the dawn (6-10 a.m.) and dusk (4-8 p . m . ) p e r i o d s (Fig. 3). The peak between 6 and 8 a.m. was largely because of coUembolans, which accounted for 92 % of the catch. Collembola represented 75 % of the arthropods captured during 8-10 a.m. The evening peak periods on this sample date were not dominated by any group and consisted of beetles (nitidulids, coccinellids, histerids and staphylinids), ants, a spider (linyphyiid), a planthopper {mirid), a wasp (scelionid), a fly (empidid) and an unidentified hemipteran nymph. Collembola were also captured in small numbers during this period. The total catch was less in CT during the other sample dates and peaks are not so obvious. The number of arthropods captured during any one 24-h period does not appear to be related to any climatic event. There was no precipitation recorded immediately before or during the 19 July sampling session. In the no-tillage system, the largest number of arthropods were captured 27 June (Fig. 4). The largest peaks occurred during 4-8 p.m. There were 25 collembola (81% of the catch), one nitidulid, one mirid, one gryllid, one larval lepidopteran and two spiders captured during this period. As with CT, the peak was not related to precipitation events.
163 30
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12o 60 I?.p 6p ','7 JUN
12o 6c 12p 6p 19 JUL
12c 60 I?p 6p 8 AUG
12(26c 12p 6p 22 AUG
12a 6el 12p 6p 12 SEPT
DATE
Fig. 3. Diurnal activity of arthropods in conventional tillage (CT) grain sorghum during five 24h periods in 1983 (27-28 J u n e = D a y 1, 19-20 July, 8-9 August, 22-23 August and 12-13 September).
20 18
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I ' ' l ' ' l ' ' l ' '
12a 6a 12p 6p 22 AUG
I ' T I ' ' I ' ' I
'
12a 6a 12p 6p 12 SEPT
DATE
Fig. 4. Diurnal activity of arthropods in no-tillage (NT) grain sorghum during five 24-h periods in 1983 (27-28 J u n e = D a y 1, 19-20 July, 8-9 August, 22-23 August and 12-13 September).
164 There were no other dominant trends for either system. W h e n data from the five sample dates are combined for each system, arthropod activity peaks during late afternoon and evening (4-8 p.m. ). Catches in the two systems were approximately equal during this period. There was also a slight activity peak early to mid-morning (6-10 a.m. ), largely from the catch in CT on 19 July. The presence of litter in N T and resulting abatement of soil moisture loss should provide a more favorable environment for many soil arthropods than the bare, often dry surface in CT. On the other hand, the bare C T soil may allow for greater movement, and trapability may then be enhanced. Collembolans may become more surface active in the dry CT plots. Greater activity in CT contrasted with work by Blumberg and Crossley (1983) in the same systems, which indicated consistently greater pitfall catches in N T when compared to CT. However, the area was in its first year of agricultural production (1978) after 10 years of fallow when their pitfall study was conducted. Activity in the C T and N T systems may have been more similar by 1983, b u t lack of replication in the present study does not allow for further comparison between the systems. ACKNOWLEDGEMENTS The authors thank Robert G. Blumberg for the design and construction of the traps. Ellis Nash, Physical Plant, University of Georgia, built the trap housings. Debbie R. Folkerts and Sally Spaulding, D e p a r t m e n t of Entomology, University of Georgia, provided technical assistance. The research was supported by the National Science Foundation through a grant directed by Drs. Eugene P. Odum and D.A. Crossley, Jr. ( N S F Nutrient-Odum, No. DEB8207206) and by a coptract, DE-AS09-76EV00641, between the U.S. Department of Energy and the University of Georgia Research Foundation Inc. REFERENCES Blumberg, A.Y. and Crossley, D.A., Jr., 1983. Comparison of soil surface arthropod populations in conventional tillage, no-tillage and old field systems. Agro-ecosystems,8: 247-253. Dondale, C.D., Redner, J.H. and Semple, R.B., 1972. Diel activity periodicities in meadow arthropods. Can. J. Zool., 50: 1155-1163. Gist, C.S, and Crossley, D.A., Jr., 1973. A method for quantifying pitfall trapping. Environ. Entomol., 2: 951-952. Granstrom, U., 1973. Pitfall traps for studying the activity of groundliving spiders (Araneida). Aquilo Ser. Zool., 14: 93-98. Greenslade, P.J.M., 1964. Pitfall trapping as a method for studying populations of carabidae (Coleoptera). J. Anita. Ecol., 33: 301-310. Hagvar, S., Ostbye, E. and Melaen, J., 1978. Pitfall catches of surface active arthropods in some high mountain habitats at Finse South Norway. II. General results at group levelwith emphasis on Opiliones, Araneida, and Coleoptera. Norw. J. Entomol., 25: 195-206. Muma, M.H., 1973. Comparison of ground surface spiders in four central Florida ecosystems. Florida Entomol., 56: 173-196. Southwood, T.R.E., 1978.Ecological Methods. Methuen, London, 391 pp. Williams, G., 1959. The seasonal and diurnal activity of the fauna sampled by pitfall traps in different habitats. J. Anim. Ecol., 28: 1-13.
159
Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands
Diurnal Activity of Soil-Surface Arthropods in Agroecosystems: Design for an Inexpensive TimeSorting Pitfall Trap ANDREA Y. BLUMBERG 1 and D.A. CROSSLEY, Jr. ~
lOffice of Agriculture, Bureau for Science and Technology, Agency for International Development, Washington, DC 20523 (U.S.A.) 2Department of Entomology and Institute of Ecology, University of Georgia, Athens, GA 30602 (U.S.A.) (Accepted for publication 13 October 1987)
ABSTRACT
Blumberg, A.Y. and Crossley, Jr., D.A., 1988. Diurnal activity of soil-surface arthropods in agroecosystems: design for an inexpensive time-sorting pitfall trap. Agric. Ecosystems Environ., 20: 159-164. The design for an inexpensive time-sorting pitfall trap is presented. The basis of the mechanism is a rotary stepping solenoid powered by lantern batteries. Traps were utilized to sample soilsurface arthropods at 2-h intervals for five 24-h periods in 1983. One trap was placed in a conventional tillage (CT) agroecosystem and one in a no-•lage (NT) agroecosystem. Soft arthropod surface activity was greatest in CT on 19 July during the dawn and dusk periods and during dusk on 27 June.
INTRODUCTION
Comparison of pitfall trap catches in different habitats affords a measure of the relative activities of surface-dwelling soil arthropods. Pitfall trapping is a widely used technique for collecting arthropods, but it is not quantitative. The number of arthropods caught is influenced not only by density but also by activity {Williams, 1959; Greenslade, 1964; Dondale et al., 1972; Granstrom, 1973 ). Activity is influenced by both mobility of the arthropod and the nature of the substrate. Pitfall trapping has been quantified by removal methods ( Gist and Crossley, 1973 ) and by mark-recapture techniques (Southwood, 1978 ). Otherwise, pitfall trapping has been used successfully as a comparison method of evaluating differences between ecosystems (Muma, 1973; Hagvar et al., 1978; Blumberg and Crossley, 1983). Diurnal activities of surface-dwelling soil arthropods can be evaluated with pitfall traps but the method is laborious. Ad0167-8809/88/$03.50
© 1988 Elsevier Science Publishers B.V.
160
Funn:.--~_oil. Surface ~-----'~ ]1/4tSoil to Top of Funnel
SampleCups Rot ary Stepping Solenoid
~
~
~
~
Batteries
TimingCircuit Fig. 1. Schematic diagram of the trapping system. The trap mechanism is housed in an aluminum box.
ditionally, the effect of trap manipulation on faunal activity in the immediate area is unknown. Presented here are the design and evaluation of a time-sorting pitfall trap which automatically changes sample cups at 2-h intervals. The trap contains 16 cups, so that a 32-h continuous sampling can be performed. The design was evaluated with measurement of diurnal activity of soil-surface arthropods in conventional tillage and continuous no-tillage grain sorghum agroecosystems. METHODS AND MATERIALS
Trap design The trap and its mechanism are enclosed in a small metal box (31 X 31 X 26 cm). The time-sorting feature permits a fresh sample cup to be rotated under the trap funnel at periodic intervals (Fig. 1 ). An aluminum housing encloses a turntable (28.5 cm in diameter) supporting the sample cups. A rotary stepping solenoid rotates the turntable at 22.5 ° intervals (16 cups total) and is powered by a set of 6-V lantern batteries. Solid state circuitry generates timed pulses and energizes the solenoid. The turntable and all fabricated metal parts are aluminum. The cups are 60ml Tupperware ® containers bolted through the turntable, A second inner cup containing ethylene glycol is inserted to hold the actual samples.
161 vcc
T-12 v
+
.toutoot
24V
v
+28
T
t
RA,
I ~-~,--d~'O"1 Relayto isolate DI-~-IT R~E~ e I c/1h "II ~PelSOT s~ikrea'ior°mfr~ °/'n°id ~
C2
4 o
$2~ D2
~
TIMER
RotorySteppin(j Solenoid
. . . .
556
IOKP~
330g
A smaller power transistor moy be utilized unless the reloy is omitted,
\
.1
Fig. 2. Schematic diagram of timing circuit. (C1 = 500 uF; C2-- 0.01 uF; D1 -- 1N4003; D2 = 1N4003; RA=2.2 M; RB=3.3 M; R c = 2 0 M).
Timing circuit The timing circuit incorporates a dual timer 556 chip (Fig. 2 ). One section operates in an astable mode, generating pulses. The frequency is determined by resistor and capacitor combinations, and can be manually triggered (or reset) by a momentary SPST ($2 in Fig. 2). These pulses trigger the other timer which operates in a monostable mode to generate resistor/capacitor controlled pulses of sufficient duration to permit the solenoid to advance one complete step. The output switches a transistor which energizes a small relay which activates the solenoid.
Solenoid and batteries The rotary stepping solenoid is a 28-V DC surplus unit. An SPST switch ($3 in Fig. 2) can disable the solenoid during testing and timing calibration in order to minimize battery use. A small hub was fitted around the switch shaft using Allen screws. This arrangement provided a threaded shaft, so that a nut could be tightened on the turntable. Five 6-V lantern batteries were connected in series and tapped to provide 30 V for the solenoid, 24 V for the relay and 12 V for the timing circuit. However, the battery voltage dipped significantly when the solenoids were energized, so
162
a separate 9-V source controlled by an SPST switch ($1 in Fig. 2) was added to energize the timing circuit. The use of screw terminal batteries facilitates battery replacement. Field evaluation
The aluminum housing is buried so that the top is slightly below the soil surface. A funnel is placed in a hole in the housing lid so that it is directed over the center of a sample cup. The housing lid is covered with soil ( and litter in N T systems). The trap is allowed to run for at least 14 h; the first cup is discarded in order to avoid the effects of disturbance when the trap is set for use.
Automated traps were evaluated in no-tillage ( N T ) and conventional tillage (CT) grain sorghum at the University of Georgia's Horseshoe Bend facility (Blumberg and Crossley, 1983). Test operations were performed during five 24-h periods between 27 June and 13 September 1983. Two traps were used, one in the CT agroecosystem and one in the N T agroecosystem. The plots used were planted in grain sorghum. Both plots were planted with winter rye the previous winter. The CT plot was ploughed and disked prior to sorghum planting; the NT plot was not cultivated at any time, so that a layer of rye mulch was present on the soil surface. The traps were allowed to 'settle' for 3 weeks prior to use, in order to minimize the effects of disturbance from the installation. RESULTS AND DISCUSSION
Numbers captured during the 2-h periods for the five sample dates in 1983 are shown in Fig. 3 (CT) and 4 ( N T ) The first time period represents a 2-h period from midnight to 2 am. The largest catches in CT occurred on 19 July during the dawn (6-10 a.m.) and dusk (4-8 p . m . ) p e r i o d s (Fig. 3). The peak between 6 and 8 a.m. was largely because of coUembolans, which accounted for 92 % of the catch. Collembola represented 75 % of the arthropods captured during 8-10 a.m. The evening peak periods on this sample date were not dominated by any group and consisted of beetles (nitidulids, coccinellids, histerids and staphylinids), ants, a spider (linyphyiid), a planthopper {mirid), a wasp (scelionid), a fly (empidid) and an unidentified hemipteran nymph. Collembola were also captured in small numbers during this period. The total catch was less in CT during the other sample dates and peaks are not so obvious. The number of arthropods captured during any one 24-h period does not appear to be related to any climatic event. There was no precipitation recorded immediately before or during the 19 July sampling session. In the no-tillage system, the largest number of arthropods were captured 27 June (Fig. 4). The largest peaks occurred during 4-8 p.m. There were 25 collembola (81% of the catch), one nitidulid, one mirid, one gryllid, one larval lepidopteran and two spiders captured during this period. As with CT, the peak was not related to precipitation events.
163 30
25
w 20 a_
co 1,5 c} o (3_ o rt-r I0 ln,"
12o 60 I?.p 6p ','7 JUN
12o 6c 12p 6p 19 JUL
12c 60 I?p 6p 8 AUG
12(26c 12p 6p 22 AUG
12a 6el 12p 6p 12 SEPT
DATE
Fig. 3. Diurnal activity of arthropods in conventional tillage (CT) grain sorghum during five 24h periods in 1983 (27-28 J u n e = D a y 1, 19-20 July, 8-9 August, 22-23 August and 12-13 September).
20 18
16 C:l
I.co Q I0 O Q. O 8 n~ -r F6 rr
I I'
I ''
I 1 ' I ' I
12a 6a 12p 6p 27 JUN
I ' ' l ' ' l '
'1''
12a 6a 12p 6p 19 JUL
I ' ' l ' ' l ' ' l ' '
12a 6a 12p 6p 8 AUG
I ' ' l ' ' l ' ' l ' '
12a 6a 12p 6p 22 AUG
I ' T I ' ' I ' ' I
'
12a 6a 12p 6p 12 SEPT
DATE
Fig. 4. Diurnal activity of arthropods in no-tillage (NT) grain sorghum during five 24-h periods in 1983 (27-28 J u n e = D a y 1, 19-20 July, 8-9 August, 22-23 August and 12-13 September).
164 There were no other dominant trends for either system. W h e n data from the five sample dates are combined for each system, arthropod activity peaks during late afternoon and evening (4-8 p.m. ). Catches in the two systems were approximately equal during this period. There was also a slight activity peak early to mid-morning (6-10 a.m. ), largely from the catch in CT on 19 July. The presence of litter in N T and resulting abatement of soil moisture loss should provide a more favorable environment for many soil arthropods than the bare, often dry surface in CT. On the other hand, the bare C T soil may allow for greater movement, and trapability may then be enhanced. Collembolans may become more surface active in the dry CT plots. Greater activity in CT contrasted with work by Blumberg and Crossley (1983) in the same systems, which indicated consistently greater pitfall catches in N T when compared to CT. However, the area was in its first year of agricultural production (1978) after 10 years of fallow when their pitfall study was conducted. Activity in the C T and N T systems may have been more similar by 1983, b u t lack of replication in the present study does not allow for further comparison between the systems. ACKNOWLEDGEMENTS The authors thank Robert G. Blumberg for the design and construction of the traps. Ellis Nash, Physical Plant, University of Georgia, built the trap housings. Debbie R. Folkerts and Sally Spaulding, D e p a r t m e n t of Entomology, University of Georgia, provided technical assistance. The research was supported by the National Science Foundation through a grant directed by Drs. Eugene P. Odum and D.A. Crossley, Jr. ( N S F Nutrient-Odum, No. DEB8207206) and by a coptract, DE-AS09-76EV00641, between the U.S. Department of Energy and the University of Georgia Research Foundation Inc. REFERENCES Blumberg, A.Y. and Crossley, D.A., Jr., 1983. Comparison of soil surface arthropod populations in conventional tillage, no-tillage and old field systems. Agro-ecosystems,8: 247-253. Dondale, C.D., Redner, J.H. and Semple, R.B., 1972. Diel activity periodicities in meadow arthropods. Can. J. Zool., 50: 1155-1163. Gist, C.S, and Crossley, D.A., Jr., 1973. A method for quantifying pitfall trapping. Environ. Entomol., 2: 951-952. Granstrom, U., 1973. Pitfall traps for studying the activity of groundliving spiders (Araneida). Aquilo Ser. Zool., 14: 93-98. Greenslade, P.J.M., 1964. Pitfall trapping as a method for studying populations of carabidae (Coleoptera). J. Anita. Ecol., 33: 301-310. Hagvar, S., Ostbye, E. and Melaen, J., 1978. Pitfall catches of surface active arthropods in some high mountain habitats at Finse South Norway. II. General results at group levelwith emphasis on Opiliones, Araneida, and Coleoptera. Norw. J. Entomol., 25: 195-206. Muma, M.H., 1973. Comparison of ground surface spiders in four central Florida ecosystems. Florida Entomol., 56: 173-196. Southwood, T.R.E., 1978.Ecological Methods. Methuen, London, 391 pp. Williams, G., 1959. The seasonal and diurnal activity of the fauna sampled by pitfall traps in different habitats. J. Anim. Ecol., 28: 1-13.