• We sampled arthropods on the three most common perennial plant species in that part of the Alvord Basin: Greasewood (Sarcobatus verniculatus), Sagebrush (Artemesia tridentata), and Spiny Hopsage (Grayia spinosa).
• Eighteen plants of each species were measured for length, width, and height to enable a volume estimate. One week prior to bagging and sampling the bugs on the plants, we removed the protruding portions of stems as a means to prepare the plants for rapid, proficient bagging.
• Three different size categories for each species were sampled to represent the species size range. Three samples per size were taken at early, mid, and late day for six days.
• One fourth of the above ground vegetation of each plant was placed in a translucent plastic bag, stems were cut, the samples were fogged with insecticide, and the closed-bag contents were incubated for a half-hour.
• Plants were shaken vigorously than removed from the bag. The debris was sifted through for arthropods and galls, and the plants were examined further for arthropods and galls.
• Arthropods and galls were preserved in 95% ethanol and taken back to Western Washington University for further study.
• Wet weight was taken of the plant samples in the Alvord Desert. At Western, plant samples were dried and above ground biomass was measured.
• Arthropods were keyed out to taxonomic orders.

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Results

• Formicids were the most common arthropods found in the sampling (Fig. 1).
• Other orders found were Arachnids, Hemipterans, Lepidopterans, Coleopterans, Orthopterans, and Dipterans (Fig. 1).
• The biomass of Greasewood and Hopsage increased exponentially with volume (Fig. 2).
• The biomass of Sage also increased with volume but then leveled off (Fig. 2).
• Greasewood had the highest abundance of arthropods and Hopsage the lowest (Table 1).
• The biomass of Sage was twice that of Greasewood and almost four times that of Hopsage (Table 1).
• Hopsage had the highest Shannon-Wiener diversity index for orders (Table 2).
• Sage and Greasewood had similar results for the S-W diversity index (Table 2).

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Conclusions

• Greasewood offered the most protection and vegetation for the insects, which explains the large diversity and abundance of insects found on the plant.
• Sage also showed diversity and abundance of insects but not as much as the Greasewood. Sage was a woodier plant with less vegetation to provide protection and nutrition for insects. More galls were found on the Sage due to its woody composition.
• Hopsage did not provide protection or much nutrition for insects. The vegetation was sparse and stems were fairly thin.
• Size of plants did play a part in the abundance and diversity of insects. With a larger volume the vegetation provided the insects with protection and nutrition.
• The whole plant sampling method was effective in representing the diversity of arthropods in the Alvord Desert.

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Figure 1 - Number of Arthropods Found on Total Sample of Plants in Alvord Desert

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Figure 2 - Volume to Biomass Regression for Vegetation in Alvord Desert

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Table 1 - Total Number of Arthropods Related to Shrub Type & Size

Shrub Characteristics	Small	Medium	Large	Combined
# Sampled	6	6	6	18
Greasewood Arthropod #	49	87	86	222
Greasewood Dry Mass (g)	780	3156	8423	12360
Sage Arthropod #	12	23	68	103
Sage Mass (g)	1667	4403	18825	24896
Hopsage Arthropod #	7	23	8	38
Hopsage Mass (g)	789	2609	5529	8926

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Figure 2 - Measures of Arthropod Diversity in Plant Samples

	Number of Plants Sampled	Number of Taxonomic Orders (per all 18 plants)	Range of # of Arthropods per Order	Total Number of Arthropods (per all  18 plants)	S-W Diversity Index, for Orders	Average Number of Arthropods per Plant Sample
Grease	18	6	1 - 33	222	0.64	12
Sage	18	6	1 - 11	103	0.62	6
Hop	18	7	1 - 2	38	0.69	2

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