Forensic pollen geolocation techniques used to identify the origin of boll weevil re-infestation

Figures & data

Figure 1. Maps of the United States of America and Texas. A. The United States of America showing College Station, Texas (C), North (N) and South (S) Carolina and Georgia (G). B. A map of Texas showing three boll weevil eradication zones: Southern Rolling Plains (SRP) zone, Southern Blacklands (SBL) zone, where Cameron is located, and Southern Texas/Winter Garden (WG) zone, where Uvalde is located.

Table I. General pollen data found in the boll weevils from the three eradication zones

	SRP	Cameron^a	Uvalde^a
Number of samples	19	8	8
Samples with pollen	17	8	8
Percentage with pollen^b	89	100	100
Number of pollen grains	192	1904	148
Range of grains per sample	2−36	105−524	5−30
Number of taxa	39	10	28
Range of taxa per sample	1−8	4−6	3−9
Note: SRP = pollen collected from the weevils captured in the Southern Rolling Plains eradication zone.
^aEach Uvalde and Cameron sample contained five weevils.
^bPercentage is rounded to the nearest whole number.

Table II. Each taxon's percentage of the total number of pollen grains per location

		SRP	Cameron	Uvalde
Alismataceae	Sagittaria	3.13
Anacardiaceae	Toxicodendron radicans			2.70
Asteraceae	Ambrosia	6.77		20.69
Asteraceae	Artemisia	3.13
Asteraceae	Carduus	3.13
Asteraceae	Iva sp. #1	4.69		2.76
Asteraceae	Iva sp. #2		3.00
Asteraceae	Solidago sp.		0.05	22.76
Asteraceae	High spine	3.13		0.69
Asteraceae	Low spine 2–6 (five types)	14.56
Asteraceae	Low spine #7	1.04		2.07
Asteraceae	Low spine 8–12 (five types)			21.58
Asteraceae	Low spine #13		94.65
Boraginaceae		0.52
Caryophyllaceae		8.85
Cheno-Am		16.67	1.40	2.07
Cupressaceae	Juniperus sp.	1.56		0.69
Cyperaceae		1.04	0.05
Euphorbiaceae		0.52
Fabaceae	Amorpha sp.	0.52		0.69
Fabaceae	Leucaena sp.	1.04		0.69
Fabaceae	Mimosa strigillosa	0.52		0.69
Fabaceae	Mimosa sp.	0.52		0.69
Fabaceae		0.52		0.69
Fagaceae	Quercus sp.	0.52
Malvaceae	Gossypium hirsutum	8.33	0.05	2.07
Pinaceae	Pinus sp.	0.52
Poaceae		6.77	0.65	4.14
Portulacaceae	Phermeranthus sp.	1.56		1.38
Salicaceae	Populus deltoides	2.08		0.69
Solanaceae	Solanum sp.		0.05
Ulmaceae	Celtis laevigata var. reticulata	1.56
Ulmaceae	Planera aquatica		0.05
Ulmaceae	Ulmus crassifolia	0.52	0.05
Urticaceae		2.08		9.66
Unknowns 2–8 (seven types)		4.20
Unknowns control 2–4 and 7–8 (five types)				2.60
Total		100.00	100.00	100.00
Note: SRP = pollen collected from the boll weevils captured in the Southern Rolling Plains eradication zone.

Figure 2. Pollen found in boll weevils collected in the Southern Rolling Plains, Southern Blacklands (Cameron) and Winter Garden (Uvalde) eradication zones. A. Cheno-Am, Amaranthus palmerii. B. Malvaceae, cotton, Gossypium hirsutum. C. Poaceae, grass. D. Asteraceae ‘low spine’ #13. E. Anacardiaceae, poison ivy, Toxicodendron radicans. F. Portulacaceae, flameflower, Phermeranthus sp. Scale bars – 50 μm (B), 20 μm (A, C–F).

Table III. Frequency of occurrence of the pollen taxa found in the boll weevil samples

Family	Scientific name	SRP	Cameron	Uvalde
Alismataceae	Sagittaria sp.	15.79
Anacardiaceae	Toxicodendron radicans			25.00
Asteraceae	Ambrosia sp.	15.79		75.00
Asteraceae	Artemisia sp.	21.05
Asteraceae	Carduus sp.	21.05		25.00
Asteraceae	Iva sp. #1	52.63
Asteraceae	Iva sp. #2		100.00
Asteraceae	Solidago sp.		12.50	62.50
Asteraceae	High spine	10.53		12.50
Asteraceae	Low spine 2–6 (five taxa)	63.16
Asteraceae	Low spine 7–12 (six taxa)			87.50
Asteraceae	Low spine #13		100.00
Boraginaceae		5.26
Caryophyllaceae		10.53
Cheno-Am		31.58	100.00	12.50
Cupressaceae	Juniperus sp.	15.79		12.50
Cyperaceae		10.52	12.50
Eurphobiaceae		5.26
Fabaceae	Amorpha sp.	5.26		12.50
Fabaceae	Leucaena sp.	5.26		12.50
Fabaceae	Mimosa strigillosa	5.26		12.50
Fabaceae	Mimosa sp.	5.26		12.50
Fabaceae		5.26		12.50
Fagaceae	Quercus sp.	5.26
Malvaceae	Gossypium hirsutum	5.26	12.50	25.00
Pinaceae	Pinus sp.	5.26
Poaceae		52.63	75.00	50.00
Portulacaceae	Phermeranthus sp.	5.26		12.50
Salicaceae	Populus deltoides	21.05		12.50
Solanaceae	Solanum sp.		12.50
Ulmaceae	Celtis laevigata var. reticulata	15.79
Ulmaceae	Planera aquatica		12.50
Ulmaceae	Ulmus crassifolia	5.26	12.50
Urticaceae		5.26		75.00
Note: SRP = pollen collected from the boll weevils captured in the Southern Rolling Plains eradication zone.