Cellular reactions of the white grub larvae, Polyphylla adspersa, against entomopathogenic nematodes

Abstract

The haemocyte reactions of the white grub larvae Polyphylla adspersa to entomopathogenic nematodes (EPN), together with the host haemocyte types, have been studied. Six types of identified haemocytes included the prohaemocytes, granulocytes, plasmatocytes, oenocytoids, coagulocytes and spherulocytes. The granulocytes were :he dominant (65.2%) haemocyte type followed by the plasmatocytes (22.1 %). Both haemocyte types encapsulate EPN. White grub larvae and last larval stage of Galleria mellonella were individually infected with monoxenic Heterorhabditis bacteriophora or Steinernema glaseri. The maximum total haemocyte counts (THC) level of the white grub larvae against the nematode S. glaseri occurred at 12 h post-injection. In addition, by 8 h post-injection, the granulocyte and plasmatocyte levels decreased. The cell reactions of the grubs against H. bacteriophora in terms of THC and differential haemocyte counts and the encapsulation rate started earlier and were more pronounced than those against S. glaseri. The maximum percentage of the encapsulation observed in the white grub larvae against S. glaseri (27.3 ± 0.7%) and H. bacteriophora (36.5 ± 3.5%) occurred at 12 and 8 h post-injection, respectively. EPN-triggered encapsulation in P. adspersa larvae was more extensive than in G. mellonella larvae.

Bacterial feeding nematodes ingest haemocytes in the haemocoel of the insectGalleria mellonella

“…Changes in total haemocyte population after nematode infection have been previously reported (Ayaad et al, 2001;Walter et al, 2008;Manachini et al, 2013;Yi et al, 2016;Lalitha et al 2018). Injection of Heterorhabditis bacteriophora or Steinernema glaseri decreased haemocyte density in the larval haemocoel of the greater wax moth Galleria mellonella (Alvandi et al, 2014). Conversely, haemocyte density was reported to increase in the haemocoel of the cotton bollworm Helicoverpa armigera larvae infected with O. sinensis (Jiao et al, 2018).…”

“…2018). Injection of Heterorhabditis bacteriophora or Steinernema glaseri decreased haemocyte density in the larval haemocoel of the greater wax moth Galleria mellonella (Alvandi et al ., 2014). Conversely, haemocyte density was reported to increase in the haemocoel of the cotton bollworm Helicoverpa armigera larvae infected with O. sinensis (Jiao et al ., 2018).…”

In Vitro Compatibility and Combined Efficacy of Entomopathogenic Nematodes with Abamectin and Imidacloprid Against the White Grub, Pentodon bispinosus Kust.

“…Scarabaeidae are a strong insect that includes many white grubs. It has an alert and responsive immune system that interacts with xenobiotics H. bacteriophora or S. glaseri can increase the immunocytes after 8-12 h after injection of the white grub larvae, Polyphylla adspersa (Alvandi et al, 2014). Successful infection of EPNs required overcoming this weak immune response (Alvandi et al, 2017).…”

Transmission Success of Entomopathogenic Nematodes Used in Pest Control

“…Many immune factors have been shown to vary in the hemolymph of the host following the entry of nematodes, including both humoral and cellular responses. For instance, many studies documented modifications through time in the hemocyte counts [ 151 , 152 , 153 ] and the enzyme activity of the host such as proteases and phenoloxidase [ 152 , 153 , 154 , 155 ]. Nematodes and their symbiotic bacteria can both inhibit their hosts’ immune system, suppressing the melanization process and depressing the antimicrobial response [ 146 , 153 , 156 ].…”