Huntsman-killing spider wasps have been observed beginning their gruesome reproduction cycle in Adelaide.

Entomologist and manager of live exhibits at the Museum of Victoria Patrick Honan explained to 891 ABC Adelaide's Spence Denny that spider wasps hunt the arachnids and use them as live hosts to incubate their larvae.

"The wasps go out, seek a live huntsman and then there is a life and death battle between the wasp and the spider," Mr Honan said.

"Most often the wasp wins."

The wasp stings and paralyses the spider and then drags it back to its mud nest.

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"They always head back [to the nest] in a straight line, and if anything is in the way they will go over the top," Mr Honan said.

A single egg is laid inside the abdomen of the huntsman.

Once hatched, the larva eats the spider from the inside out.

"They tend to leave the vital organs till last, as the spider needs those to stay alive and the wasp wants the huntsman to be as fresh as possible to be consumed," Mr Honan said.

"It seems cruel and gruesome to us, but that is the way nature is."

Mr Honan said one out of every 10 insects were parasitic, meaning they live either on or in other insects.

"It's a way of life for a lot of creatures," he said.

A spider wasp takes another unwilling host back to the nest. ( Supplied: Hollie Wilson )

Summer is peak breeding season for the spider wasps.

"Seeing a large orange and black or brilliant blue wasp dragging a large spider is something people tend not to forget," Mr Honan said.

891 ABC Adelaide Facebook fans have shared their stories of encounters with spider wasps.

"My mum had one of these drop a paralysed huntsman into her lap as she was getting into her car," Eve Rogers wrote.

"The wasp wasn't going anywhere until she got her hunty back.

"Meanwhile Mum was having a myocardial infarction [heart attack]."