{execute @e[type=item,name=cobweb] ~ ~ ~ execute @p[r=2] ~ ~ ~ effect @a speed 30 2 true}

is working well

but

{execute @e[type=item,name=spider_eye] ~ ~ ~ execute @p[r=2] ~ ~ ~ effect @a speed 30 2 true}

is not working

{spider eye}

{spider.eye} {spidereye} are not working too