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Table 1 Indices of aggregation (Ia)* values recorded at different countries on entomopathogenic nematode (EPN) populations with various sampling methods and units (Abd-Elgawad 2019)

From: Towards sound use of statistics in nematology

EPN investigated population

Method of measuring EPNs

Ia value

Notes (geographical zone)

References

Heterorhabditis bacteriophora-infective stage juveniles (IJs) used in different distribution patterns

EPN-infected greater wax moth larvae over time

Mean values were less than one but differed significantly until 20 weeks after adding EPNs

The values indicate a more uniform distribution than a random one (New Jersey/USA)

Wilson et al. (2003)

Natural Steinernema feltiae and S. affine populations in grassland

IJs grouped to 4 groups of different physiological ages

The values were in the range 1.27–1.45, group II was the most aggregated stage

All values showed clumped distribution patterns (Merelbeke/Belgium)

Spiridonov et al. (2007)

H. bacteriophora or S. carpocapsae-infected greater wax moth larvae used within 24 h of starting IJ exit to planted fields and grassy plots

IJs of H. bacteriophora and S. carpocapsae recovered from greater wax moth larvae baits used after the cadavers

Mean values range < 1 to > 2. They differed between nematode species in bait traps and between control methods at 48 h and 16 days after placing the cadavers, respectively

Distribution patterns after dispersing from a grassy border plots into the adjacent cultivated field plots were more clumped for H. bacteriophora than for S. carpocapsae (Ohio/USA)

Bal et al. (2017)

H. indica natural populations in citrus and mango grove

EPN-infected greater wax moth larvae

0.913

Ia refers to uniform distribution (Giza/Egypt)

Abd-Elgawad (2020)

  1. *Ia = the observed value of distance to regularity/the mean randomized value (Perry 1995)