Journal of The Lepidopterists' Society (JLS): 1964-18(1)1-Denmark.htm

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	Journal of The Lepidopterists' Society Volume 18 1964 Number 1

	EVALUATION OF AN INSECT LIGHT TRAP DESIGNED TO SEPARATE BEETLES AND MOTHS¹ by H. A. Denmark Entomology Section, Fla. Dept. Agrig., Gainesville, Florida Insect light traps have been used for over 80 years for collection, population and migration studies, as a survey tool, and in attempts to control insects (Frost, 1952). Comstock (1879) and Riley (1885) described several light traps that were used for the control of the cotton leaf-worm (Alabama argillacea (Hiibn.)). Evans (1907) and Banks (1909) tested light traps for collecting nocturnal insects. The New Jersey light trap, developed about 1931 is still used today to sample mosquito populations. Many designs and light sources have been evaluated and the results reported. Reed, et al. (1935) designed a trap with a light source to attract the cigarette beetle (Lasioderma serricorne (Fab.)) and a fan to suck the beetles into a jar as a means of control. Weiss (1943) reported on the behavior of insects attracted to light of various wave lengths and color. The trap designed and reported on here resulted from the need to catch and separate beetles and moths. The principle of this light trap is based on the habit of beetles flying against an object, folding their wings and dropping. Although the habits of moths are not as predictable, many species will land on the light trap and move upwards. Some species remain in place after being attracted to light while others make quick irregular flights and often fall short distances before recovering. Design.— A 15-watt black light fluorescent lamp is mounted vertically inside a plastic cylinder 6 inches in diameter (Fig. 1). The cylinder is open at both ends with a metal baffle at the top and middle sections. The entrance to the inner canister is baffled, and a cone baffle is located iContribution No. 28, Entomology Section, Division of Plant Industry, Florida Department of Agriculture, Gainesville, Florida.

	1



2	Denmark: Differential trap		Vol.18: no.l

below the entrance. Four fin baffles extend vertically on four sides of the plastic cylinder. The large collection funnel contains a cone baffle to prevent insects from escaping once they fall into the funnel and to prevent direct entry of raindrops. The opening in the bottom of the outer canister permits rain water to drain. The top cover extends over the edge of the large collecting funnel, and the trap is hung in place by a hook in the center of the cover. The inner canister is coated with plaster-of-Paris and saturated with ethyl acetate as a killing agent. The outer canister is filled with alcohol to the top of the drain. This trap will be referred to as a modified trap,

		top entrance baffle plastic cylinder black light element baffle bottom entrance baffle cone baffle inner canister (dry) collecting funnel cone baffle
		outer canister (wet)

Fig. 1. Modified black light trap.



1964	Journal of the Lepidopterists Society*	3

%£

Fig. 2. Standard trap. Traps of this design have been furnished states parti- cipating in the Cooperative Economic Insect Survey by the Agricultural Research Service, Agricultural Engineering Research Division.

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and the trap used to compare catches as the standard trap.

Several standard traps (Fig. 2) furnished by the United States Department of Agriculture, Agricultural Engineering Research Division, Agricultural Engineering Department, have been operated in various parts of Florida for the past 7 years. In Homestead, Belle Glade, and Sanford, the water beetle population is very high. If the insects are caught in a dry canister, the beetles destroy the moths before the beetles are killed. The beetles then become coated with moth scales making them unfit for collections and difficult to identify. If the insects are killed in alcohol, the moths are often ruined and the beetles are also coated with scales from the moths.

The standard and modified traps were operated at Gainesville, Florida


		TABLE 1
		MODIFIED	TRAP
DATE					STANDARD TRAP
DATE	Laphygma j	rugiperda	Coleoptera
	Dry	Wet	Wet \|	Dry	Dry
7/19/62	14	23	81	0	43
7/20/62	15	23	103	0	46
7/21/62	3	6	47	0	14
7/22/62	10	13	84	1	25
7/23/62	12	17	92	0	34
7/24/62	10	18	101	0	41
7/25/62	10	13	123	2	24
8/1/62	10	14	96	0	26
8/2/62	16	41	112	1	48
8/3/62	20	78	136	2	82
8/4/62	20	46	127	0	63
8/5/62	6	17	84	1	36
8/6/62	6	24	91	0	41
8/7/62	6	9	87	0	30
9/1/62	4	6	83	1	7
9/2/62	6	6	111	1	15
9/3/62	9	13	86	0	15
9/4/62	10	14	74	0	23
9/5/62	13	15	97	0	25
9/6/62	17	15	103	1	29
9/7/62	11	12	127	2	36
TOTALS	228	423	2,045	12	703
AVE.	10.9	20.1	97.4	.5	33.4

Average combined catches of modified trap are 0.92 as great as the standard catch and the modified dry catch is 0.5 as great as the wet catch.

1964

Journal of the Lepidopterists' Society

to compare catches and to test the efficiency of the modified trap to separate moths and Coleoptera. Six species of moths common to the area were selected arbitrarily for the comparisons; all six are noctuids.

Results.— An average of less than one Coleoptera was caught in the inner canister. Occasionally a Coleoptera would alight on the plastic cylinder, crawl up the side, and fall into the inner canister (Tables 1-6). Large numbers of Coleoptera were caught in the outer canister of both the modified trap and the standard trap.

The average standard trap catch was approximately as many moths as the combined average catch of the modified trap. The ratio of the number of moths caught in the inner canister as opposed to the outer canister of the modified trap ranged from 0.5:1 to 1:1, respectively (Tables 1-6).


	TABLE 2
	MODIFIED TRAP
DATE	Agrotis subterranea	Coleoptera	STANDARD TRAP
	Dry , Wet	Wet Dry	Dry

7/19/62 10 13 81 0 17

7/20/62 5 14 103 0 16

7/21/62 4 6 47 0 10

7/22/62 4 13 84 1 17

7/23/62 4 6 92 0 9

7/24/62 12 16 101 0 18

7/25/62 4 11 123 2 14

8/1/62 2 6 96 0 11

8/2/62 10 11 112 1 14

8/3/62 10 15 136 2 18

8/4/62 12 17 127 0 19

8/5/62 13 16 84 1 26

8/6/62 11 17 91 0 24

8/7/62 11 18 87 0 26

9/1/62 10 16 83 1 21

9/2/62 11 15 111 1 24

9/3/62 15 21 86 0 29

9/4/62 11 11 74 0 13

9/5/62 10 11 97 0 17

9/6/62 11 14 103 1 18

9/7/62 11 10 127 2 15

TOTALS 191 277 2,045 12 376

AVE. 9.1 13.2 97.4 0.5 18

Average combined catches in the modified trap are greater than the standard catch and the modified dry catch is 0.7 as great as the wet catch.

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TABLE 3


	MODIFIED TRAP
DATE	Heliothis zea	Coleoptera	STANDARD TRAP
	Dry Wet	Wet Dry	Dry

7/19/62

7/20/62

7/21/62

7/22/62

7/23/62

7/24/62

7/25/62

8/1/62

8/2/62

8/3/62

8/4/62

8/5/62

8/6/62

8/7/62

9/1/62

9/2/62

9/3/62

9/4/62

9/5/62

9/6/62

9/7/62

11 13 81 0 24

10 14 103 0 18

11 13 47 0 17

11 11 84 1 14

12 16 92 0 24 19 16 101 0 31 42 73 123 2 97 17 18 96 0 32

10 20 112 1 23 12 15 136 2 18

11 17 127 0 31

16 22 84 1 29

17 18 91 0 27

10 15 87 0 28 28 40 83 1 58

12 13 111 1 16

11 15 86 0 25 14 16 74 0 29

10 19 97 0 22

11 12 103 1 15 11 11 127 2 13

306 407 2,045 12 591

14.6 19.4 97.4 0.5 28.1

TOTALS

AVE.

Average combined catches in the modified trap are greater than the standard catch and the modified dry catch is 0.75 as great as the wet catch.

Discussion.— Coleoptera and moths can be separated successfully by enclosing the black light element in a baffled plastic cylinder. The cylinder may reduce the numbers of moths caught in the inner canister as compared to the number caught in the outer canister (Tables 1-6). The number of Coleoptera caught in the inner canister was always low and occasionally a leafhopper or fly was caught also. Dr. Wallace C. Harding, Jr. reported high numbers of Cicadellidae and Diptera caught

1964

Journal of the Lepidopterists' Society

TABLE 4


	MODIFIED TRAP
DATE	Mods latipes	Coleoptera	STANDARD TRAP
	Dry Wet	Wet Dry	Dry

8/20/62 18 10 137 2 21

8/21/62 15 12 129 3 16

8/22/62 12 10 131 0 13

8/23/62 14 14 124 0 16

8/24/62 10 11 96 1 12

8/25/62 13 12 106 0 12

8/26/62 14 11 89 0 15

9/1/62 13 11 83 1 15

9/2/62 14 17 111 1 16

9/3/62 14 18 86 0 24

9/4/62 19 29 74 0 40

9/5/62 20 26 97 0 44

9/6/62 19 21 103 1 40

9/7/62 15 22 127 2 39

10/1/62 31 17 81 0 36

10/2/62 14 30 74 0 19

10/3/62 7 19 78 1 42

10/4/62 13 15 66 0 48

10/5/62 16 19 73 0 39

10/6/62 18 18 81 1 43

10/7/62 11 21 74 1 42

TOTALS 320 363 2,020 14 592

AVE. 15.3 17.3 96 0.7 28.1

Average combined catches in the modified trap are greater than the standard catch and the modified dry catch is 0.88 as great as the wet catch.

in the inner canister of a modified trap he operated, located at Fairland, Maryland, 1961. His trap did not have the baffles on the inside of the plastic cylinder. Location of traps and differences in insect populations probably will effect the number of insects caught in the inner and outer canisters.

The evaluation of the modified trap as a survey tool to separate beetles and moths is difficult even when a single species is compared. There are

Denmark: Differential trap

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often wide ranges in the number of specimens caught on any two dates. The variation in numbers caught is also evident in the standard trap. Since most catches of the standard trap were about as great or greater than the modified trap, the plastic cylinder was tested to determine the effects, if any, on the wave length of the light source by Mr. James M. Stanley, Agricultural Engineer, United States Department of Agriculture, Blacksburg, Virginia. Figure 3 shows that the plastic cylinder transmitted more lower wave length energy than a 40-watt black light fluorescent

TABLE 5


	MODIFIED TRAP
DATE	Anticarsia gemmatilis	Coleoptera	STANDARD TRAP
	Dry \| Wet	Wet Dry	Dry

8/20/62 11 11 137 2 16

8/21/62 10 11 129 3 18

8/22/62 8 11 131 0 17

8/23/62 12 10 124 0 19

8/24/62 11 12 96 1 16

8/25/62 11 11 106 0 21

8/26 62 9 12 89 0 24

9,1/62 13 12 83 1 19

9/2/62 13 16 111 1 26

9/3/62 11 14 86 0 28

9/4/62 21 16 74 0 37

9/5/62 17 7 97 0 31

9/6/62 14 12 103 1 27

9/7/62 16 15 127 2 32

10/1/62 13 12 81 0 29

10/2/62 13 19 74 0 21

10/3/62 17 18 78 1 37

10/4/62 11 16 66 0 36

10 5/62 19 7 73 0 34

10/6/62 16 16 81 1 37

10/7/62 12 15 74 1 31

TOTALS 278 273 2,020 14 556

AVE. 13.2 13.0 96 0.7 26.5

Average combined catches in the modified trap are equal to the standard catch and the modified dry catch is equal to the modified wet catch.

1964

Journal of the Lepidopterists' Society

lamp. It is thought that the lower wave lengths attracted more insects; therefore, the difference in the catches for the standard and modified traps must be in the design rather than in light source. It would be desirable to separate all moths and beetles as they are attracted to a light trap. To date no light trap has been designed to do this. The modified trap discussed in this paper will separate about 50 per cent of some species of moths from beetles. For other species, however, it is not as efficient.


		TABLE 6
		MODIFIED	TRAP
DATE	Alabama	argillacea	Coleoptera		STANDARD TRAP
	Dry	Wet	Wet	Dry	Dry
8/20/62	11	11	137	2	24
8/21/62	11	13	129	3	27
8/22/62	12	12	131	0	25
8/23/62	12	11	124	0	24
8/24/62	11	11	96	1	23
8/25/62	10	12	106	0	22
8/26/62	11	12	89	0	24
9/1/62	12	12	83	1	26
9/2/62	12	11	111	1	24
9/3/62	11	10	86	0	23
9/4/62	10	11	74	0	21
9/5/62	11	12	97	0	24
9/6/62	10	10	103	1	21
9/7/62	11	11	127	2	23
10/1/62	10	10	81	0	21
10/2/62	12	12	74	0	24
10/3/62	14	18	78	1	37
10/4/62	15	20	66	0	43
10/5/62	10	11	73	0	29
10/6/62	12	12	81	1	20
10/7/62	12	12	74	1	26
TOTALS	240	254	2,020	14	531
AVE.	11.4	12.1	96	0.7	25.3

The average combined catches in the modified trap are 0.92 as great as the standard catch and the modified dry catch is C\95 as great as the wet catch.

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Vol.18: no.l

1.00 .90 .80 .70 .60 .50 L_


			/ \
				""^
[-	Cylinder, 6.000 0.125 in.wall	in		O
k	? /		*I '*	Energy distribution of 40 watt blacklight
k	V		1 1 1 1 1	1 fluorescent lamp
			*1 1*	\
[-			*1 1 1* /	\ V \ \ \
			/	\ \
\-			/ / *1 1*	n \ ii ^x r~i i
		/	t	< i i
	l^T ___\|____IX	/	1 1 1___	_i______i ^J-t--' )______1

.40

.30

.20

.10 L

2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 Nominal Wavelength, Angstroms

Fig. 3. A comparison of wave lengths of a 15-watt black light element through a 0.125 inch plastic cylinder and a 40-watt black light element.

References

Banks, Nathan, 1909. Directions for collecting and preserving insects. Rull.

U.S. not. mus. 67: 45-47. Comstock, J. H., 1879. Report upon cotton insects: pp.262-275. [Prepared under

the direction of the Commissioner of Agriculture.] U. S. Dept. Agr., Wash.,

D. C. Evans, J. D., 1907. Practical and popular entomology No. 20 — A homemade and

effective insect trap. Canad. ent. 39: 150-152. Frost, S. W., 1952. Light traps for insect collection, survey and control. Bull.

Agr. exp. sta. state college, Venn. 550. Reed, W. D., A. W. Morrill, Jr., & E. M. Livingstone, 1935. Trapping experiments

for the control of the cigarette beetle. U. S. dept. agr. circ. 356. Riley, C. V., 1885. Directions for collection and preserving insects. Bull. U. S. nat.

mus. 39: 45. Weiss, Harry B., 1943. Color perception in insects. Journ. econ. ent. 36: 1-17.

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